Nanoparticle-mediated delivery of cytokines for maintenance of the regulatory T cell phenotype

ABSTRACT

Compositions for delivery of growth factors needed for stable Tregs and methods of use thereof are provided. In preferred embodiments, the compositions can induce, increase, or enhance a functionally robust induced CD4 Treg population (e.g., Foxp3+ Treg) in vivo or ex vivo. The compositions generally include delivery vehicles including TGF-β and IL-2. Delivery vehicles include, for example, polymeric particles, silica particles, liposomes, or multilamellar vesicles. The TGF-β and IL-2 are typically co-loaded into, attached to the surface of, and/or enclosed within the delivery vehicle into the same particle for simultaneous co-delivery to cells such as T cells. Preferably the delivery vehicles are targeted to CD4. The compositions and cells treated therewith can be used in various methods of treating, for example, inflammation, inflammatory and autoimmune diseases and disorders, and inducing or maintaining tolerance including graft and transplant tolerance.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/155,055, filed on May 15, 2016, which is acontinuation-in-part of U.S. patent application Ser. No. 14/394,161,filed Oct. 13, 2014, which is a U.S. national phase application filedunder 35 U.S.C. § 371 claiming benefit to International PatentApplication No. PCT/US2013/036487, filed Apr. 12, 2013, which isentitled to priority to U.S. Provisional Application No. 61/623,486,filed Apr. 12, 2012, U.S. Provisional Application No. 61/747,624, filedDec. 31, 2012, and U.S. Provisional Application No. 61/747,614, filedDec. 31, 2012, each of which applications is incorporated herein byreference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under AI056363 awardedby National Institute of Health. The government has certain rights inthe invention.

FIELD OF THE INVENTION

The present invention is generally in the field of delivery of thecombination of IL-2 and TGF-β, using nanoparticulates, which may betargeted to CD4 expressed by a desired cell or tissue type to enhanceefficacy

BACKGROUND OF THE INVENTION

CD4+ T cells represent an intriguing checkpoint for therapeuticintervention in immune-mediated diseases. This is because thedifferentiation and subsequent function of CD4+ T cells can becontrolled through: 1) manipulation of the T cell receptor (TCR)signaling, 2) modulation of co-stimulatory or inhibitory molecules, and3) influencing the cytokine milie u. In this context, the cytokinemilieu is important for the orchestration of lineage development stepstowards either effector T cell (Teff) or regulatory T cell (Treg)phenotypes. As such, the role of cytokines in the differentiation ofCD4+ T cells serves as an excellent example to describe the commondifficulties encountered in the therapeutic manipulation of immune cellfunction in physiopathological conditions. One major challenge is therequirement for targeted and highly localized delivery of cytokines toCD4+ cells and not to other cells, because of the pleiotropic effects ofcytokines on certain immune cell populations. Another attribute ofcytokines is redundancy, and one more intriguing aspect of the immuneresponse is that the combination of certain cytokines can exertwell-defined effects only on selected immune cell populations. Forexample, the combination of TGF-β and IL-2 during antigenic stimulationresults in the differentiation of naïve CD4+ T cells into Tregs.However, the simultaneous signaling by TGF-β and the inflammatorycytokine IL-6 not only suppresses the formation of tolerogenic Tregs,but also induces the development of proinflammatory Th17 cells, whichhave a key promoting role in the pathogenesis of autoimmune disease suchas SLE.

Although Tregs have an unequivocal protective role in autoimmunedisease, the possible therapeutic use of cytokines for the induction ofTregs is complicated by the fact that an indiscriminate use in vivo ofeither TGF-β or IL-2 would not be a viable option. In particular, TGF-βis pro-fibrotic, while IL-2 acts on all T cells (thus expandingconcurrently both Tregs and Teff populations). Another technicalchallenge is that a generalized delivery of TGF-β and IL-2 in vivo couldresult in synergy or counter-regulation of Tregs outcome if othercytokines are present concomitantly in the local milieu.

Tregs that express the Forkhead box protein transcription factor (Foxp3)are a critical subset of CD4+ T cells that maintain homeostasis duringinfection and tolerance toward self-epitopes. Mutations in Foxp3 canlead to the wasting multiorgan autoimmune condition, IPEX(immune-dysregulation, poly-endocrinopathy, enteropathy, X-linked) inhumans. In many common autoimmune diseases such as multiple sclerosisand type 1 diabetes, Tregs become unable to control pathogenic CD4 andCD8 effector cells because of defects on numbers or function. For thisreason, strategies to correct these defects and boost their stabilityhave been garnering attention as potential alternatives to theconventional broadly immunosuppressive agents currently in use.

Foxp3+ Tregs are now classified as one of three subsets. The majority ofendogenous Tregs, now called nTregs, originate in the thymus and arecalled tTregs. Others called pTregs are induced from naïve T cells inthe periphery. nTregs characteristically display chromatin demethylationat the Foxp3 locus. Tregs require the cytokines IL-2 and TGF-β forfitness and survival. Tregs similar to pTregs called iTregs can also beinduced from naïve CD4+ cells ex-vivo by suboptimal TCR signaling in thepresence of IL-2 and TGF-β. iTregs were initially believed to beunstable because chromatin remained methylated at the Foxp3 locus.However, in an inflammatory microenvironment nTregs are also unstableand can convert to an effector phenotype. Importantly, recent studiescomparing the stability of mouse and human nTregs and iTregs in aninflammatory microenvironment have revealed that only iTregs remainFoxp3+ and can reverse established disease. These findings are supportedby the report that Tregs induced in-vivo can also reverse disease inanimal models of multiple sclerosis and autoimmune diabetes. However,the methods used to induce these protective iTregs are probably tootoxic for translation into a practical immunotherapy.

Thus it is an objection of the invention to provide compositions andmethods of use thereof able to safely provide the growth factors neededfor stable Tregs.

It is a further object of the invention to provide compositions andmethods of use thereof to generate a functionally robust induce CD4 Tregpopulation in-vivo.

SUMMARY OF THE INVENTION

Compositions and methods for directed delivery of active agents toimmune cells are provided. The compositions generally include a deliveryvehicle such as polymeric particles, silica particles, liposomes, ormultilamellar vesicles with TGF-β and IL-2 co-loaded into, attached tothe surface of, and/or enclosed within. Preferably the delivery vehicleis a polymeric particle, for example a PLGA nanoparticle. The deliveryvehicles are optionally, but preferably, targeted to CD4 by a targetingmoiety such as anti-CD4 antibody.

Experiments demonstrate the importance of antigen persistence mediatedby particulate platforms and its role in the long-term appearance ofeffector memory cellular response. Systemic administration ofCD4-targeted cytokine-loaded nanoparticles (“NPs”) was able to promotetolerance through expansion of host regulatory cells in murine allograftmodels. CD4-targeted TGF-β/IL-2 NPs alone induced a 3% increase in Tregfrequency in the spleen and mesenteric lymph nodes of healthy mice.Donor-specific transfusion of splenocytes pretreated with CD4-targetedLIE nanoparticles NPs resulted in a 4-fold increase in donor-specificTregs and significantly enhanced tolerance of fully mismatched heartallografts from 7 to 12 days.

Targeted nanoparticles (NPs) offer an innovative solution to thechallenges outlined above. Compared to soluble cytokines, NPs have theadvantage to: 1) shift the biodistribution of cytokines selectively totarget cells, thereby localizing cytokine effects to cells of interest;2) deliver relatively high local doses (if needed), while diminishingthe need for large systemic doses and related side effects; 3) exploitexisting synergies or counter-regulatory mechanisms through thesimultaneous delivery of multiple components under a single platform.

Under these considerations, the use of NPs to augment the provenbeneficial effects of adoptive T cell transfer or direct immunotherapycan represent a significant innovation that offers advantages overexisting best practices, since it optimizes the induction of protectivemechanisms of action at the target site while minimizing concomitantside effects. Additional benefits in the use of NPs are: 4) the capacityto deliver bioactive molecules specifically to target cells oversustained periods of time; 5) a delivery under dynamic physiologicconditions (such as those occurring after adoptive transfer), with theadvantage of a fine tuning for optimization of the response.

Thus compositions including particles, including polymer nanoparticles,loaded with a combination of TGF-β and IL-2, optionally, but preferablytargeted to CD4 are provided. The composition can be in an amounteffective amount to increase Treg frequency, number, or a combinationthereof in a subject. The compositions can be administered to subjectsin need thereof to increase Treg frequency, number, or a combinationthereof in the subject. The composition can be administeredsystemically. Methods of increasing donor-specific Tregs are alsoprovided. Exemplary methods include treating isolated cells, for exampleleukocytes, ex vivo with particles co-loaded with TGF-β and IL-2. Thecells can be administered to a subject in need thereof to induce orincrease tolerance, for example graft tolerance, in the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph showing quantification of nanoparticle sizedistribution by Nanosight particle tracking system. FIG. 1B is a linegraph showing release kinetics of TGF-β (circles) and IL-2 (diamonds),measured by ELISA.

FIG. 2A is a bar graph showing TGF-β and IL-10 concentrations in thesupernatant were measure by ELISA of mixed splenocytes cultured withTGF-β and IL-2 in soluble (5 ng/ml and 10 U/ml, respectively) ornano-encapsulated form (0.1 mg nanoparticle/ml) to induce CD25+Foxp3+Tregs. FIG. 2B is a bar graph showing % Foxp3+ CD25+ of untreatedlymphocytes or lymphocytes treated with soluble or nanoparticle (“nano”)encapsulated TGF-β and IL-2 (Results from 4 independent experiments areplotted (***P<0.001)). FIG. 2C is a dose-response curve showing doseresponses of nano-encapsulated (solid line), and soluble (hatched line)cytokine. Values are percentages of CD4+ lymphocytes. FIG. 2D is adose-response curve showing proliferation of IL-2 dependent CTRL-1842cells dosed with nano-encapsulated (nano, solid line) or free (control,hatched line) IL-2 and quantified after 4 days by Coulter Counter.

FIG. 3A is a bar graph showing Foxp3 induction after CD4+GFP-cells weresorted, stained with CellTrace Violet, and stimulated with CD3/CD28beads for 4 days in the presence of load or empty NPs or free cytokinecontrols at dosages of 20 ug/ml and 200 ug/ml NP doses. FIG. 3B is aCell Trace Violet mean intensity is plotted (*p<0.05, **p<0.01,***p<0.001 from untreated control. ##p<0.01 from soluble control) of theexperiment described in FIG. 3B.

FIG. 4A is a schematic of the experimental setup shows representativecell numbers over time. The left-hand panel shows suppressor cells(Thy1.1−) were generated by either free IL-2 and TGF-β (10 U/ml and 5ng/ml, respectively), or nanoparticles (0.1 mg/ml) for 5 days (inductionphase). Foxp3+ Tregs were quantified by FACS, washed, and added invarious relative Treg fractions to CD4+Thy1.1+CD25− splenocytes(responder cells). These cultures were stimulated with anti-CD3/CD28beads in 96-well flat-bottom plates at a 1:2 bead-to-cell ratio for anadditional 4 days (suppression phase). During this period, respondercells proliferated while Foxp3 expression on suppressor cells decreased.The center panel shows that following the suppression phase, suppressorand responder cells were identified by surface expression of Thy1.1 andincorporation of CellTracc Violet as shown in the representative FACSplot. The right hand panel shows that each generation of proliferatedresponder cells was gated as shown in the representative histogram, andgated frequencies were used to calculate proliferative index, PI, asdescribed in Table 2. FIG. 4B is a representative CellTrace Violetdilutions across titrated initial Treg fractions shows that suppressorcells treated with nanoparticles preferentially suppressed responderproliferation. FIG. 4C is a line graph showing the proliferative indexof responder cells co-cultured with suppressor cells generated withsoluble cytokines (triangles) vs. nano-encapsulated cytokines (circles)(*p<0.05, **p<0.005, ***p<0.001). FIG. 4D is a line graph showing Foxp3expression of suppressor cells plotted as a function of initial Tregfraction. FIG. 4E is a line graph showing total numbers of remainingFoxp3+ suppressor cell numbers plotted as a function of initial Tregfraction. (*p<0.05, **p<0.005, ***p<0.001).

FIG. 5 is a line graph showing Foxp3 expression monitored over time onmixed splenocytes treated with soluble (triangles) or nano-encapsulated(circles) TGF-β and IL-2 for a 3 day induction phased before washing thecells and replating. Control cells (circles) were replenished withsoluble cytokine after washing. (*p<0.05 between nano-encapsulated andsoluble using a 2-tailed T test on day 9 Foxp3 expression).

FIG. 6A is a bar graphs showing coumarin-6 (ng) in tissues harvestedfive days after I.P. injection of 2.0 mg coumarin-6 labelednanoparticles. Coumarin-6 was measured by fluorescence microscopy. FIG.6B is a bar graph showing Tregs plotted as percentages of CD4+ T cells.2.0 mg TGF-β IL-2 CD4-targeted nanoparticles were injected I.P. and micewere sacrificed after 5 days for FACS analysis. (*p<0.05 vs. untreatedcontrols). FIG. 6C is dot plot showing Treg numbers per tissue in theexperiment described in FIG. 6B.

DETAILED DESCRIPTION OF THE INVENTION I. Definitions

“Small molecule,” as used herein, refers to molecules with a molecularweight of less than about 2000 g/mol, more preferably less than about1500 g/mol, most preferably less than about 1200 g/mol.

“Hydrogel,” as used herein, refers to a water-swellable polymeric matrixformed from a three-dimensional network of macromolecules held togetherby covalent or non-covalent crosslinks, that can absorb a substantialamount of water (by weight) to form a gel.

“Nanoparticle”, as used herein, generally refers to a particle having adiameter from about 10 nm up to, but not including, about 1 micron,preferably from 100 nm to about 1 micron. The particles can have anyshape. Nanoparticles having a spherical shape are generally referred toas “nanospheres”.

“Molecular weight” as used herein, generally refers to the relativeaverage chain length of the bulk polymer, unless otherwise specified. Inpractice, molecular weight can be estimated or characterized usingvarious methods including gel permeation chromatography (GPC) orcapillary viscometry. GPC molecular weights are reported as theweight-average molecular weight (Mw) as opposed to the number-averagemolecular weight (Mn). Capillary viscometry provides estimates ofmolecular weight as the inherent viscosity determined from a dilutepolymer solution using a particular set of concentration, temperature,and solvent conditions.

“Mean particle size” as used herein, generally refers to the statisticalmean particle size (diameter) of the particles in a population ofparticles. The diameter of an essentially spherical particle may referto the physical or hydrodynamic diameter. The diameter of anon-spherical particle may refer preferentially to the hydrodynamicdiameter. As used herein, the diameter of a non-spherical particle mayrefer to the largest linear distance between two points on the surfaceof the particle. Mean particle size can be measured using methods knownin the art, such as dynamic light scattering.

“Monodisperse” and “homogeneous size distribution”, are usedinterchangeably herein and describe a population of nanoparticles ormicroparticles where all of the particles are the same or nearly thesame size. As used herein, a monodisperse distribution refers toparticle distributions in which 90% of the distribution lies within 15%of the median particle size, more preferably within 10% of the medianparticle size, most preferably within 5% of the median particle size.

“Active Agent”, as used herein, refers to a physiologically orpharmacologically active substance that acts locally and/or systemicallyin the body. An active agent is a substance that is administered to apatient for the treatment (e.g., therapeutic agent), prevention (e.g.,prophylactic agent), or diagnosis (e.g., diagnostic agent) of a diseaseor disorder.

Abbreviations

-   CD=cluster of differentiation-   DMSO=dimethylsulfoxide-   ELISA=enzyme-linked immunosorbent assay-   FACS=fluorescent activated cell sorting-   FBS=fetal bovine serum-   GFP=green fluorescent protein-   HCl=hydrochloric acid-   mTOR=mammalian target of rapamycin-   NaCl=sodium chloride-   PE=phycoerythrin-   PFA=paraformaldehyde-   TCR=T cell receptor

II. Compositions

Compositions and methods of use thereof for delivery of growth factorsneeded for stable Tregs are provided. In preferred embodiments, thecompositions and methods of use thereof can induce, increase, or enhancea functionally robust induced CD4 Treg population (e.g., Foxp3+ Treg,iTreg, etc., as discussed above) in-vivo.

The compositions generally include delivery vehicles including TGF-β andIL-2. Delivery vehicles include, for example, polymeric particles,silica particles, liposomes, or multilamellar vesicles. The TGF-β andIL-2 can be loaded into, attached to the surface of, and/or enclosedwithin the delivery vehicle into separate particles and delivered inparallel or tandem. In the most preferred embodiments, TGF-β and IL-2are co-loaded, attached, and/or enclosed within the same deliveryvehicle. Preferably, the delivery vehicles are targeted to CD4.

Nanoparticle compositions are discussed in more detail below. Inpreferred embodiments, the nanoparticles are composed ofpoly(lactic-co-glycolic) acid (PLGA). PLGA particles have been usedextensively for the controlled delivery of various proteins to many celltypes. PLGA is an FDA approved polymer that degrades via hydrolysis, andnanoparticles made from PLGA release encapsulated proteins over thecourse of several days to weeks as the polymer matrix erodes. Inartificial antigen-presentation systems comprised of PLGAmicroparticles, sustained IL-2 release has been shown to enhance CD8 Tcell proliferation and function due to local accumulation of cytokinesat the immunological synapse, mimicking paracrine cytokine delivery.PLGA micro- and nanoparticles surface-conjugated with antibodies havebeen shown to facilitate attachment to specific cell types.

The particles can generate and maintain tunable cytokine conditions at atarget cell surface. The Examples below illustrate Treg induction byCD4-targeted nanoparticles co-encapsulating TGF-β and IL-2. Theexperiments illustrate the CD4 cell-binding capacity of the particlesand their ability to generate Tregs in-vitro and in-vivo.Nanoparticle-induced Tregs are more efficacious in both theirsuppressive function and demonstrate enhanced phenotypic stability incomparison to conventionally induced Tregs.

A. Nanoparticle Formation

The nanoparticles are typically formed using an emulsion process, singleor double, using an aqueous and a non-aqueous solvent. Typically, thenanoparticles contain a minimal amount of the non-aqueous solvent aftersolvent removal. Preferred methods of preparing these nanoparticles aredescribed in the examples.

In one embodiment, nanoparticles are prepared using emulsion solventevaporation method. A polymeric material is dissolved in a waterimmiscible organic solvent and mixed with a drug solution or acombination of drug solutions. The water immiscible organic solvent ispreferably a GRAS ingredient such as chloroform, dichloromethane, andacyl acetate. The drug can be dissolved in, but is not limited to, oneor a plurality of the following: acetone, ethanol, methanol, isopropylalcohol, acetonitrile and Dimethyl sulfoxide (DMSO). An aqueous solutionis then added into the resulting mixture solution to yield emulsionsolution by emulsification. The emulsification technique can be, but notlimited to, probe sonication or homogenization through a homogenizer.

In another embodiment, nanoparticles are prepared usingnanoprecipitation methods or microfluidic devices. A polymeric materialis mixed with a drug or drug combinations in a water miscible organicsolvent. The water miscible organic solvent can be one or more of thefollowing: acetone, ethanol, methanol, isopropyl alcohol, acetonitrileand Dimethyl sulfoxide (DMSO). The resulting mixture solution is thenadded to an aqueous solution to yield nanoparticle solution. The agentsmay be associated with the surface of, encapsulated within, surroundedby, and/or distributed throughout the polymeric matrix of the particles.

In another embodiment, nanoparticles are prepared by the self-assemblyof the amphiphilic polymers, optionally including hydrophilic and/orhydrophobic polymers, using emulsion solvent evaporation, a single-stepnanoprecipitation method, or microfluidic devices.

Two methods to incorporate targeting moieties into the nanoparticlesinclude: i) conjugation of targeting ligands to the hydrophilic region(e.g. PEG) of polymers prior to nanoparticle preparation; and ii)incorporation of targeting molecules onto nanoparticles where the PEGlayer on the nanoparticle surface can be cleaved in the presence of achemical or enzyme at tissues of interest to expose the targetingmolecules.

Particles may be microparticles or nanoparticles. Nanoparticles arepreferred for intertissue application, penetration of cells, and certainroutes of administration. The nanoparticles may have any desired sizefor the intended use. The nanoparticles may have any diameter from 10 nmto 1,000 nm. The nanoparticle can have a diameter from 10 nm to 900 nm,from 10 nm to 800 nm, from 10 nm to 700 nm, from 10 nm to 600 nm, from10 nm to 500 nm, from 20 nm from 500 nm, from 30 nm to 500 nm, from 40nm to 500 nm, from 50 nm to 500 nm, from 50 nm to 400 nm, from 50 nm to350 nm, from 50 nm to 300 nm, or from 50 nm to 200 nm. In preferredembodiments the nanoparticles can have a diameter less than 400 nm, lessthan 300 nm, or less than 200 nm.

The average diameters of the nanoparticles are typically between about50 nm and about 500 nm, preferably between about 50 nm and about 350 nm.In some embodiments, the average diameters of the nanoparticles areabout 100 nm. The zeta potential of the nanoparticles is typicallybetween about −50 mV and about +50 mV, preferably between about −25 mVand +25 mV, most preferably between about −10 mV and about +10 my.

The following are exemplary materials and methods of making polymericNPs.

1. Materials for Making Polymeric NPs

a. Polymers

The nanoparticle can contain one or more hydrophilic polymers.Hydrophilic polymers include cellulosic polymers such as starch andpolysaccharides; hydrophilic polypeptides; poly(amino acids) such aspoly-L-glutamic acid (PGS), gamma-polyglutamic acid, poly-L-asparticacid, poly-L-serine, or poly-L-lysine; polyalkylene glycols andpolyalkylene oxides such as polyethylene glycol (PEG), polypropyleneglycol (PPG), and poly(ethylene oxide) (PEO); poly(oxyethylated polyol);poly(olefinic alcohol); polyvinylpyrrolidone);poly(hydroxyalkylmethacrylamide); poly(hydroxyalkylmethacrylate);poly(saccharides); poly(hydroxy acids); poly(vinyl alcohol), andcopolymers thereof.

The nanoparticle can contain one or more hydrophobic polymers. Examplesof suitable hydrophobic polymers include polyhydroxyacids such aspoly(lactic acid), poly(glycolic acid), and poly(lactic acid-co-glycolicacids); polyhydroxyalkanoates such as poly3-hydroxybutyrate orpoly4-hydroxybutyrate; polycaprolactones; poly(orthoesters);polyanhydrides; poly(phosphazenes); poly(lactide-co-caprolactones);polycarbonates such as tyrosine polycarbonates; polyamides (includingsynthetic and natural polyamides), polypeptides, and poly(amino acids);polyesteramides; polyesters; poly(dioxanones); poly(alkylene alkylates);hydrophobic polyethers; polyurethanes; polyetheresters; polyacetals;polycyanoacrylates; polyacrylates; polymethylmethacrylates;polysiloxanes; poly(oxyethylene)/poly(oxypropylene) copolymers;polyketals; polyphosphates; polyhydroxyvalerates; polyalkylene oxalates;polyalkylene succinates; poly(maleic acids), as well as copolymersthereof.

In certain embodiments, the hydrophobic polymer is an aliphaticpolyester. In preferred embodiments, the hydrophobic polymer ispoly(lactic acid), poly(glycolic acid), or poly(lactic acid-co-glycolicacid).

The nanoparticle can contain one or more biodegradable polymers.Biodegradable polymers can include polymers that are insoluble orsparingly soluble in water that are converted chemically orenzymatically in the body into water-soluble materials. Biodegradablepolymers can include soluble polymers crosslinked by hydolyzablecross-linking groups to render the crosslinked polymer insoluble orsparingly soluble in water.

Biodegradable polymers in the nanoparticle can include polyamides,polycarbonates, polyalkylenes, polyalkylene glycols, polyalkyleneoxides, polyalkylene terepthalates, polyvinyl alcohols, polyvinylethers, polyvinyl esters, polyvinyl halides, polyvinylpyrrolidone,polyglycolides, polysiloxanes, polyurethanes and copolymers thereof,alkyl cellulose, hydroxyalkyl celluloses, cellulose ethers, celluloseesters, nitro celluloses, polymers of acrylic and methacrylic esters,methyl cellulose, ethyl cellulose, hydroxypropyl cellulose,hydroxy-propyl methyl cellulose, hydroxybutyl methyl cellulose,cellulose acetate, cellulose propionate, cellulose acetate butyrate,cellulose acetate phthalate, carboxylethyl cellulose, cellulosetriacetate, cellulose sulphate sodium salt, poly (methyl methacrylate),poly(ethylmethacrylate), poly(butylmethacrylate),poly(isobutylmethacrylate), poly(hexlmethacrylate),poly(isodecylmethacrylate), poly(lauryl methacrylate), poly (phenylmethacrylate), poly(methyl acrylate), poly(isopropyl acrylate),poly(isobutyl acrylate), poly(octadecyl acrylate), polyethylene,polypropylene poly(ethylene glycol), poly(ethylene oxide), poly(ethyleneterephthalate), poly(vinyl alcohols), poly(vinyl acetate, poly vinylchloride polystyrene and polyvinylpryrrolidone, derivatives thereof,linear and branched copolymers and block copolymers thereof, and blendsthereof. Exemplary biodegradable polymers include polyesters, poly(orthoesters), poly(ethylene imines), poly(caprolactones),poly(hydroxybutyrates), poly(hydroxyvalerates), polyanhydrides,poly(acrylic acids), polyglycolides, poly(urethanes), polycarbonates,polyphosphate esters, polyphosphazenes, derivatives thereof, linear andbranched copolymers and block copolymers thereof, and blends thereof.

The nanoparticles can contain one or more amphiphilic polymers.Amphiphilic polymers can be polymers containing a hydrophobic polymerblock and a hydrophilic polymer block. The hydrophobic polymer block cancontain one or more of the hydrophobic polymers above or a derivative orcopolymer thereof. The hydrophilic polymer block can contain one or moreof the hydrophilic polymers above or a derivative or copolymer thereof.In preferred embodiments the amphiphilic polymer is a di-block polymercontaining a hydrophobic end formed from a hydrophobic polymer and ahydrophilic end formed of a hydrophilic polymer. In some embodiments, amoiety can be attached to the hydrophobic end, to the hydrophilic end,or both.

In preferred embodiments the nanoparticles contain a first amphiphilicpolymer having a hydrophobic polymer block, a hydrophilic polymer block,and targeting moiety conjugated to the hydrophilic polymer block; and asecond amphiphilic polymer having a hydrophobic polymer block and ahydrophilic polymer block but without the targeting moiety. Thehydrophobic polymer block of the first amphiphilic polymer and thehydrophobic polymer block of the second amphiphilic polymer may be thesame or different. Likewise, the hydrophilic polymer block of the firstamphiphilic polymer and the hydrophilic polymer block of the secondamphiphilic polymer may be the same or different.

In particularly preferred embodiments the nanoparticle containsbiodegradable polyesters or polyanhydrides such as poly(lactic acid),poly(glycolic acid), and poly(lactic-co-glycolic acid). Thenanoparticles can contain one more of the following polyesters:homopolymers including glycolic acid units, referred to herein as “PGA”,and lactic acid units, such as poly-L-lactic acid, poly-D-lactic acid,poly-D,L-lactic acid, poly-L-lactide, poly-D-lactide, andpoly-D,L-lactide, collectively referred to herein as “PLA”, andcaprolactone units, such as poly(ε-caprolactone), collectively referredto herein as “PCL”; and copolymers including lactic acid and glycolicacid units, such as various forms of poly(lactic acid-co-glycolic acid)and poly(lactide-co-glycolide) characterized by the ratio of lacticacid:glycolic acid, collectively referred to herein as “PLGA”; andpolyacrylates, and derivatives thereof. Exemplary polymers also includecopolymers of polyethylene glycol (PEG) and the aforementionedpolyesters, such as various forms of PLGA-PEG or PLA-PEG copolymers,collectively referred to herein as “PEGylated polymers”. In certainembodiments, the PEG region can be covalently associated with polymer toyield “PEGylated polymers” by a cleavable linker.

The nanoparticles can also contain one or more polymer conjugatescontaining end-to-end linkages between the polymer and a targetingmoiety or a detectable label. For example, a modified polymer can be aPLGA-PEG-peptide block polymer.

The nanoparticles can contain one or a mixture of two or more polymers.The nanoparticles may contain other entities such as stabilizers,surfactants, or lipids. The nanoparticles may contain a first polymerhaving a targeting moiety and a second polymer not having the targetingmoiety. By adjusting the ratio of the targeted and non-targetedpolymers, the density of the targeting moiety on the exterior of theparticle can be adjusted.

The nanoparticles can contain an amphiphilic polymer having ahydrophobic end, a hydrophilic end, and a targeting moiety attached tothe hydrophilic end. In some embodiments the amphiphilic macromoleculeis a block copolymer having a hydrophobic polymer block, a hydrophilicpolymer block covalently coupled to the hydrophobic polymer block, and atargeting moiety covalently coupled to the hydrophilic polymer block.For example, the amphiphilic polymer can have a conjugate having thestructure A-B-X where A is a hydrophobic molecule or hydrophobicpolymer, preferably a hydrophobic polymer, B is a hydrophilic moleculeor hydrophilic polymer, preferably a hydrophilic polymer, and X is atargeting moiety. Preferred amphiphilic polymers include those where Ais a hydrophobic biodegradable polymer, B is PEG, and X is a targetingmoiety that targets, binds, and/or adheres to a target.

In some embodiments the nanoparticle contains a first amphiphilicpolymer having the structure A-B-X as described above and a secondamphiphilic polymer having the structure A-B, where A and B in thesecond amphiphilic macromolecule are chosen independently from the A andB in the first amphiphilic macromolecule, although they may be the same.

b. Active Agents

The particles are typically loaded with TGF-β and/or IL-2. In someembodiments, the particles include one or more additional active agents.

i. TGF-β

Transforming growth factor beta (TGF-β, TGF-β1, TGF-beta, etc.) is apolypeptide member of the transforming growth factor beta superfamily ofcytokines. It is a secreted protein that performs many cellularfunctions, including the control of cell growth, cell proliferation,cell differentiation and apoptosis. TGF-β can promote either T-helper 17cells (Th17) or regulatory T-cells (Treg) lineage differentiation in aconcentration-dependent manner At high concentrations, leads toFOXP3-mediated suppression of RORC and down-regulation of IL-17expression, favoring Treg cell development.

Nucleic acid and protein sequences for TGF-β are known in the art. See,for example, UniProtKB—P01137 (TGFB1_HUMAN) and the amino acid sequenceprovided therein (P01137-1: Length:390 Mass (Da):44,341, Last modified:Feb. 1, 1991-v2) and Human mRNA for transforming growth factor-beta(TGF-beta) GenBank: X02812.1 GI:37092 and the mRNA and amino acidsequences provided there, all the forgoing of which is specificallyincorporated by reference in its entirety.

ii. IL-2

Interleukin-2 (IL-2) is an interleukin cytokine signaling molecule. IL-2has important roles in immune function, tolerance and immunity,primarily via its direct effects on T cells. In the thymus, it preventsautoimmune diseases by promoting the differentiation of certain immatureT cells into regulatory T cells, which suppress other T cells that areotherwise primed to attack normal healthy cells in the body. Nucleicacid and protein sequences for IL-2 are known in the art. See, forexample, UniProtKB—P60568 (IL2_HUMAN) and the amino acid sequenceprovided therein (P60568-1: Length:153 Mass (Da):17,628 Last modified:Jul. 21, 1986-v1) and Human mRNA encoding interleukin-2 (IL-2) alymphozyte regulatory molecule GenBank: V00564.1 GI:33780 and the mRNAand amino acid sequences provided there, all the forgoing of which isspecifically incorporated by reference in its entirety.

iii. Additional Active Agents

In some embodiments, the same or different particles include additionalactive agents. Additional active agents to be delivered includetherapeutic, nutritional, diagnostic, and prophylactic agents. Theactive agents can be small molecule active agents or biomacromolecules,such as proteins, polypeptides, or nucleic acids. Suitable smallmolecule active agents include organic and organometallic compounds. Thesmall molecule active agents can be a hydrophilic, hydrophobic, oramphiphilic compound. Exemplary therapeutic agents that can beincorporated into, CD4+ T-cell epitopes, cytokines, chemotherapeuticagents, radionuclides, small molecule signal transduction inhibitors,photothermal antennas, monoclonal antibodies, immunologic dangersignaling molecules, other immunotherapeutics, enzymes, antibiotics,antivirals, anti-parasites (helminths, protozoans), growth factors,growth inhibitors, hormones, hormone antagonists, antibodies andbioactive fragments thereof (including humanized, single chain, andchimeric antibodies), antigen and vaccine formulations (includingadjuvants), peptide drugs, anti-inflammatories, immunomodulators(including ligands that bind to Toll-Like Receptors (including but notlimited to CpG oligonucleotides) to activate the innate immune system,molecules that mobilize and optimize the adaptive immune system,molecules that activate or up-regulate suppressor or regulatory T-cells,agents that promote uptake of particles into cells, nutraceuticals suchas vitamins, and oligonucleotide drugs (including DNA, RNAs, antisense,aptamers, small interfering RNAs, ribozymes, external guide sequencesfor ribonuclease P, and triplex forming agents).

Exemplary diagnostic agents include paramagnetic molecules, fluorescentcompounds, magnetic molecules, and radionuclides, x-ray imaging agents,and contrast agents.

In certain embodiments, the particles include one or moreimmunomodulatory agents. Exemplary immunomodulatory agents includecytokines, xanthines, interleukins, interferons, oligodeoxynucleotides,glucans, growth factors (e.g., TNF, CSF, GM-CSF and G-CSF), hormonessuch as estrogens (diethylstilbestrol, estradiol), androgens(testosterone, HALOTESTIN® (fluoxymesterone)), progestins (MEGACE®(megestrol acetate), PROVERA® (medroxyprogesterone acetate)), andcorticosteroids (prednisone, dexamethasone, hydrocortisone).

c. Moieties attached to Particles

The surface of the particles can be modified to facilitate targetingthrough the attachment of targeting molecules and other ligands. Thesecan be proteins, peptides, nucleic acid molecules, lipids, saccharidesor polysaccharides that bind to a receptor or other molecule on thesurface of a targeted cell. The degree of specificity can be modulatedthrough the selection of the targeting molecule. For example, antibodiesare very specific. The targeting moiety of the nanoparticle can be anantibody or antigen binding fragment thereof. These can be polyclonal,monoclonal, fragments, recombinant, or single chain, many of which arecommercially available or readily obtained using standard techniques.T-cell specific molecules can be bound to the surface of the particle.The targeting molecules may be conjugated to the terminus of one or morePEG chains present on the surface of the particle.

The targeting moieties should can have an affinity for a cell-surfacereceptor or cell-surface antigen on the target cells. The targetingmoieties may result in internalization of the particle within the targetcell.

The degree of specificity with which the particles are targeted can bemodulated through the selection of a targeting molecule with theappropriate affinity and specificity. For example, a targeting moietycan be a polypeptide, such as an antibody that specifically recognizesan immune cell marker such as CD4.

CD4 (cluster of differentiation 4) is a glycoprotein found on thesurface of immune cells such as T helper cells, monocytes, macrophages,and dendritic cells. Like many cell surface receptors/markers, CD4 is amember of the immunoglobulin superfamily. It has four immunoglobulindomains (D1 to D4) that are exposed on the extracellular surface of thecell: D1 and D3 resemble immunoglobulin variable (IgV) domains, while D2and D4 resemble immunoglobulin constant (IgC) domains CD4 uses its D1domain to interact with the β2-domain of MHC class II molecules. T cellsexpressing CD4 molecules (and not CD8) on their surface, therefore, arespecific for antigens presented by MHC II and not by MHC class I (theyare MHC class II-restricted). MHC class I contains Beta-2 microglobulin.The short cytoplasmic/intracellular tail (C) of CD4 contains a specialsequence of amino acids that allow it to interact with the Ick molecule.

Nucleic acid and protein sequences for CD4 are known in the art. See,for example, UniProtKB—P01730 (CD4_HUMAN) and the amino acid sequenceprovided therein (P01730-1: Length:458, Mass (Da):51,111, Last modified:Nov. 1, 1988-v1) and Human T-cell surface glycoprotein T4 mRNA, completecds GenBank: M12807.1 GI:179141 and the mRNA and amino acid sequencesprovided there, all the forgoing of which is specifically incorporatedby reference in its entirety.

In preferred embodiments, the targeting moiety targets an extracellularportion of CD4. The domains of CD4 are known in the art. See, forexample, UniProtKB—P01730, which provides the following domainstructure:

Feature key Position(s) Length Description Topological domain^(i) 26-396 371 Extracellular Transmembrane^(i) 397-418 22 HelicalTopological domain^(i) 419-458 40 Cytoplasmic

Some embodiments include one or more additional targeting moieties.Suitable targeting molecules that can be used to direct nanoparticles tocells and tissues of interest, as well as methods of conjugating targetmolecules to nanoparticles, are known in the art. See, for example,Ruoslahti, et al. Nat. Rev. Cancer, 2:83-90 (2002). The targeting moietycan specifically recognize and bind to a target molecule specific for acell type, a tissue type, or an organ. The target molecule can be a cellsurface polypeptide, lipid, or glycolipid. The target molecule can be areceptor that is selectively expressed on a specific cell surface, atissue or an organ. Cell specific markers can be for specific types ofcells including, but not limited to stem cells, skin cells, blood cells,immune cells, muscle cells, nerve cells, cancer cells, virally infectedcells, and organ specific cells. The cell markers can be specific forendothelial, ectodermal, or mesenchymal cells. Targeting molecules canalso include neuropilins and endothelial targeting molecules, integrins,selectins, and adhesion molecules. Targeting molecules can be covalentlybound to particles using a variety of methods known in the art.

Exemplary types of targeting moieties that can be used to target CD4and/or other targets are discussed below.

i. Peptide Targeting Moieties

In a preferred embodiment, the targeting moiety is a peptide. Thetargeting peptides can be covalently associated with the polymer and thecovalent association can be mediated by a linker. The peptides target toactively growing (angiogenic) vascular endothelial cells. Thoseangiogenic endothelial cells frequently appear in metabolic tissues suchas adipose tissues.

ii. Antibody Targeting Moieties

The targeting moiety can be an antibody or an antigen-binding fragmentthereof. The antibody can be any type of immunoglobulin that is known inthe art. For instance, the antibody can be of any isotype, e.g., IgA,IgD, IgE, IgG, IgM, etc. The antibody can be monoclonal or polyclonal.The antibody can be a naturally-occurring antibody, e.g., an antibodyisolated and/or purified from a mammal, e.g., mouse, rabbit, goat,horse, chicken, hamster, human, etc. Alternatively, the antibody can bea genetically-engineered antibody, e.g., a humanized antibody or achimeric antibody. The antibody can be in monomeric or polymeric form.The antigen binding portion of the antibody can be any portion that hasat least one antigen binding site, such as Fab, F(ab′)₂, dsFv, sFv,diabodies, and triabodies. In certain embodiments, the antibody is asingle chain antibody.

iii. Aptamer Targeting Moieties

Aptamers are oligonucleotide or peptide sequences with the capacity torecognize virtually any class of target molecules with high affinity andspecificity. Aptamers bind to targets such as small organics, peptides,proteins, cells, and tissues. Unlike antibodies, some aptamers exhibitstereoselectivity. The aptamers can be designed to bind to specifictargets expressed on cells, tissues or organs.

c. Additional Moieties

The particles can contain one or more polymer conjugates containingend-to-end linkages between the polymer and a moiety. The moiety can bea targeting moiety, a detectable label, or a therapeutic, prophylactic,or diagnostic agent. For example, a polymer conjugate can be aPLGA-PEG-phosphonate. The additional targeting elements may refer toelements that bind to or otherwise localize the nanoparticles to aspecific locale. The locale may be a tissue, a particular cell type, ora subcellular compartment. The targeting element of the nanoparticle canbe an antibody or antigen binding fragment thereof, an aptamer, or asmall molecule (less than 500 Daltons). The additional targetingelements may have an affinity for a cell-surface receptor orcell-surface antigen on a target cell and result in internalization ofthe particle within the target cell.

In some embodiments, a cell penetrating peptide, also known as cellpermeable peptides, protein transduction domains (PTDs), membranetranslocating sequences (MTSs) and Trojan peptides, (for example astuimulus-responsive cell penetrating peptide) is a conjugated to theparticle. Cell penetrating peptides include, but are not limited to,virus-derived or mimicking polymers such as TAT, influenza fusionpeptide, rabies virus glycoprotein fragment (RVG), neuropilin,penetratin, and polyarginines. Anaspec has commercially available CPPs.

d. Imaging Agents

The particles can also contain a detectable label, such as aradioisotope, a fluorophore (e.g., fluorescein isothiocyanate (FITC),phycoerythrin (PE)), an enzyme (e.g., alkaline phosphatase, horseradishperoxidase), element particles (e.g., gold particles) or a contrastagent. These may be encapsulated within, dispersed within, or conjugatedto the polymer.

For example, a fluorescent label can be chemically conjugated to apolymer of the nanoparticle to yield a fluorescently labeled polymer. Inother embodiments the label is a contrast agent. A contrast agent refersto a substance used to enhance the contrast of structures or fluidswithin the body in medical imaging. Contrast agents are known in the artand include, but are not limited to agents that work based on X-rayattenuation and magnetic resonance signal enhancement. Suitable contrastagents include iodine and barium.

2. Methods of Making Particles

a. Polymer Conjugates

Methods of polymer synthesis are described, for instance, in Braun etal. (2005) Polymer Synthesis: Theory and Practice. New York, N.Y.:Springer. The polymers may be synthesized via step-growthpolymerization, chain-growth polymerization, or plasma polymerization.

In some embodiments an amphiphilic polymer is synthesized starting froma hydrophobic polymer terminated with a first reactive coupling groupand a hydrophilic polymer terminated with a second reactive couplinggroup capable of reacting with the first reactive coupling group to forma covalent bond. One of either the first reactive coupling group or thesecond reactive coupling group can be a primary amine, where the otherreactive coupling group can be an amine-reactive linking group such asisothiocyanates, isocyanates, acyl azides, NHS esters, sulfonylchlorides, aldehydes, glyoxals, epoxides, oxiranes, carbonates, arylhalides, imidoesters, carbodiimides, anhydrides, and fluorophenylesters. One of either the first reactive coupling group or the secondreactive coupling group can be an aldehyde, where the other reactivecoupling group can be an aldehyde reactive linking group such ashydrazides, alkoxyamines, and primary amines. One of either the firstreactive coupling group or the second reactive coupling group can be athiol, where the other reactive coupling group can be a sulfhydrylreactive group such as maleimides, haloacetyls, and pyridyl disulfides.

In preferred embodiments a hydrophobic polymer terminated with an amineor an amine-reactive linking group is coupled to a hydrophilic polymerterminated with complimentary reactive linking group. For example, anNHS ester activated PLGA can be formed by reacting PLGA-CO(OH) with NHSand a coupling reagent such as dicyclohexylcarbodiimide (DCC) orethyl(dimethylaminopropyl) carbodiimide (EDC). The NHS ester activatedPLGA can be reacted with a hydrophilic polymer terminated with a primaryamine, such as a PEG-NH₂ to form an amphiphilic PLGA-b-PEG blockcopolymer.

In some embodiments a conjugate of an amphiphilic polymer with atargeting moiety is formed using the same or similar coupling reactions.In some embodiments the conjugate is made starting from a hydrophilicpolymer terminated on one end with a first reactive coupling group andterminated on a second end with a protective group. The hydrophilicpolymer is reacted with a targeting moiety having a reactive group thatis complimentary to the first reactive group to form a covalent bondbetween the hydrophilic polymer and the targeting moiety. The protectivegroup can then be removed to provide a second reactive coupling group,for example to allow coupling of a hydrophobic polymer block to theconjugate of the hydrophilic polymer with the targeting moiety. Ahydrophobic polymer terminated with a reactive coupling groupcomplimentary to the second reactive coupling group can then becovalently coupled to form the conjugate. Of course, the steps couldalso be performed in reverse order, i.e. a conjugate of a hydrophobicpolymer and a hydrophilic polymer could be formed first followed bydeprotection and coupling of the targeting moiety to the hydrophilicpolymer block.

In some embodiments a conjugate is formed having a moiety conjugated toboth ends of the amphiphilic polymer. For example, an amphiphilicpolymer having a hydrophobic polymer block and a hydrophilic polymerblock may have targeting moiety conjugated to the hydrophilic polymerblock and an additional moiety conjugated to the hydrophobic polymerblock. In some embodiments the additional moiety can be a detectablelabel. In some embodiments the additional moiety is a therapeutic,prophylactic, or diagnostic agent. For example, the additional moietycould be a moiety used for radiotherapy. The conjugate can be preparedstarting from a hydrophobic polymer having on one end a first reactivecoupling group and a another end first protective group and ahydrophilic polymer having on one end a second reactive coupling groupand on another end a second protective group. The hydrophobic polymercan be reacted with the additional moiety having a reactive couplinggroup complimentary to the first reactive coupling group, therebyforming a conjugate of the hydrophobic polymer to the additional moiety.The hydrophilic polymer can be reacted with a targeting moiety having areactive coupling group complimentary to the second reactive couplinggroup, thereby forming a conjugate of the hydrophilic polymer to thetargeting moiety. The first protective group and the second protectivegroup can be removed to yield a pair of complimentary reactive couplinggroups that can be reacted to covalently link the hydrophobic polymerblock to the hydrophilic polymer block.

b. Emulsion Methods

In some embodiments, a multimodal nanoparticle is prepared using anemulsion solvent evaporation method. For example, a polymeric materialis dissolved in a water immiscible organic solvent and mixed with a drugsolution or a combination of drug solutions. In some embodiments asolution of a therapeutic, prophylactic, or diagnostic agent to beencapsulated is mixed with the polymer solution. The polymer can be, butis not limited to, one or more of the following: PLA, PGA, PCL, theircopolymers, polyacrylates, the aforementioned PEGylated polymers, theaforementioned Polymer-drug conjugates, the aforementionedpolymer-peptide conjugates, or the aforementioned fluorescently labeledpolymers, or various forms of their combinations. The drug molecules canbe, but are not limited to, one or a more of the following: PPARgammaactivators (e.g. Rosiglitazone,(RS)-5-[4-(2-[methyl(pyridin-2-yl)amino]ethoxy)benzyl]thiazolidine-2,4-dione,Pioglitazone,(RS)-5-(4-[2-(5-ethylpyridin-2-yl)ethoxy]benzyl)thiazolidine-2,4-dione,Troglitazone,(RS)-5-(4-[(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)methoxy]benzyl)thiazolidine-2,4-dioneetc.), prostagladin E2 analog (PGE2,(5Z,11α,13E,15S)-7-[3-hydroxy-2-(3-hydroxyoct-1-enyl)-5-oxo-cyclopentyl]hept-5-enoicacid etc.), beta3 adrenoceptor agonist (CL 316243, Disodium5-[(2R)-2-[[(2R)-2-(3-Chlorophenyl)-2-hydroxyethyl]amino]propyl]-1,3-benzodioxole-2,2-dicarboxylatehydrate, etc.), Fibroblast Growth Factor 21 (FGF-21), Irisin, RNA, DNA,chemotherapeutic compounds, nuclear magnetic resonance (NMR) contrastagents, or combinations thereof. The water immiscible organic solvent,can be, but is not limited to, one or more of the following: chloroform,dichloromethane, and acyl acetate. The drug can be dissolved in, but isnot limited to, one or more of the following: acetone, ethanol,methanol, isopropyl alcohol, acetonitrile and Dimethyl sulfoxide (DMSO).

In some embodiments the polymer solution contains one or more polymerconjugates as described above. The polymer solution can contain a firstamphiphilic polymer conjugate having a hydrophobic polymer block, ahydrophilic polymer block, and a targeting moiety conjugated to thehydrophilic end. In preferred embodiments the polymer solution containsone or more additional polymers or amphiphilic polymer conjugates. Forexample the polymer solution may contain, in addition to the firstamphiphilic polymer conjugate, one or more hydrophobic polymers,hydrophilic polymers, lipids, amphiphilic polymers, polymer-drugconjugates, or conjugates containing other targeting moieties. Bycontrolling the ratio of the first amphiphilic polymer to the additionalpolymers or amphiphilic polymer conjugates, the density of the targetingmoieties can be controlled. The first amphiphilic polymer may be presentfrom 1% to 100% by weight of the polymers in the polymer solution. Forexample, the first amphiphilic polymer can be present at 10%, 20%, 30%,40%, 50%, or 60% by weight of the polymers in the polymer solution.

An aqueous solution is then added into the resulting mixture solution toyield emulsion solution by emulsification. The emulsification techniquecan be, but not limited to, probe sonication or homogenization through ahomogenizer. The plaque-targeted peptides or fluorophores or drugs maybe associated with the surface of, encapsulated within, surrounded by,and/or distributed throughout the polymeric matrix of this inventiveparticle.

c. Nanoprecipitation Method

In another embodiment, a multimodal nanoparticle is prepared usingnanoprecipitation methods or microfluidic devices. A polymeric materialis mixed with a drug or drug combinations in a water miscible organicsolvent. The polymer can be, but is not limited to, one or more of thefollowing: PLA, PGA, PCL, their copolymers, polyacrylates, theaforementioned PEGylated polymers, the aforementioned Polymer-drugconjugates, the aforementioned polymer-peptide conjugates, or theaforementioned fluorescently labeled polymers, or various forms of theircombinations. The drug molecules can be, but are not limited to, one ormore of the following: PPARgamma activators (e.g. Rosiglitazone,(RS)-5-[4-(2-[methyl(pyridin-2-yl)amino]ethoxy)benzyl]thiazolidine-2,4-dione,Pioglitazone,(RS)-5-(4-[2-(5-ethylpyridin-2-yl)ethoxy]benzyl)thiazolidine-2,4-dione,Troglitazone,(RS)-5-(4-[(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)methoxy]benzyl)thiazolidine-2,4-dioneetc.), prostagladin E2 analog (PGE2,(5Z,11α,13E,15S)-7-[3-hydroxy-2-(3-hydroxyoct-1-enyl)-5-oxo-cyclopentyl]hept-5-enoicacid etc.), beta3 adrenoceptor agonist (CL 316243, Disodium5-[(2R)-2-[[(2R)-2-(3-Chlorophenyl)-2-hydroxyethyl]amino]propyl]-1,3-benzodioxole-2,2-dicarboxylatehydrate, etc.), RNA, DNA, chemotherapeutic compounds, nuclear magneticresonance (NMR) contrast agents, or combinations thereof. The watermiscible organic solvent, can be, but is not limited to, one or more ofthe following: acetone, ethanol, methanol, isopropyl alcohol,acetonitrile and Dimethyl sulfoxide (DMSO). The resulting mixturesolution is then added to a polymer non-solvent, such as an aqueoussolution, to yield nanoparticle solution. The plaque-targeted peptidesor fluorophores or drugs may be associated with the surface of,encapsulated within, surrounded by, and/or distributed throughout thepolymeric matrix of this inventive particle.

d. Microfluidics

Methods of making nanoparticles using microfluidics are known in theart. Suitable methods include those described in U.S. Patent ApplicationPublication No. 2010/0022680 A1 by Karnik et al. In general, themicrofluidic device comprises at least two channels that converge into amixing apparatus. The channels are typically formed by lithography,etching, embossing, or molding of a polymeric surface. A source of fluidis attached to each channel, and the application of pressure to thesource causes the flow of the fluid in the channel. The pressure may beapplied by a syringe, a pump, and/or gravity. The inlet streams ofsolutions with polymer, targeting moieties, lipids, drug, payload, etc.converge and mix, and the resulting mixture is combined with a polymernon-solvent solution to form the nanoparticles having the desired sizeand density of moieties on the surface. By varying the pressure and flowrate in the inlet channels and the nature and composition of the fluidsources nanoparticles can be produced having reproducible size andstructure.

e. Other Methodologies

Solvent Evaporation.

In this method the polymer is dissolved in a volatile organic solvent,such as methylene chloride. The drug (either soluble or dispersed asfine particles) is added to the solution, and the mixture is suspendedin an aqueous solution that contains a surface active agent such aspoly(vinyl alcohol). The resulting emulsion is stirred until most of theorganic solvent evaporated, leaving solid microparticles. The resultingmicroparticles are washed with water and dried overnight in alyophilizer. Microparticles with different sizes (0.5-1000 microns) andmorphologies can be obtained by this method. This method is useful forrelatively stable polymers like polyesters and polystyrene.

However, labile polymers, such as polyanhydrides, may degrade during thefabrication process due to the presence of water. For these polymers,the following two methods, which are performed in completely anhydrousorganic solvents, are more useful.

Hot Melt Microencapsulation.

In this method, the polymer is first melted and then mixed with thesolid particles. The mixture is suspended in a non-miscible solvent(like silicon oil), and, with continuous stirring, heated to 5° C. abovethe melting point of the polymer. Once the emulsion is stabilized, it iscooled until the polymer particles solidify. The resultingmicroparticles are washed by decantation with petroleum ether to give afree-flowing powder. Microparticles with sizes between 0.5 to 1000microns are obtained with this method. The external surfaces of spheresprepared with this technique are usually smooth and dense. Thisprocedure is used to prepare microparticles made of polyesters andpolyanhydrides. However, this method is limited to polymers withmolecular weights between 1,000-50,000.

Solvent Removal.

This technique is primarily designed for polyanhydrides. In this method,the drug is dispersed or dissolved in a solution of the selected polymerin a volatile organic solvent like methylene chloride. This mixture issuspended by stirring in an organic oil (such as silicon oil) to form anemulsion. Unlike solvent evaporation, this method can be used to makemicroparticles from polymers with high melting points and differentmolecular weights. Microparticles that range between 1-300 microns canbe obtained by this procedure. The external morphology of spheresproduced with this technique is highly dependent on the type of polymerused.

Spray-Drying.

In this method, the polymer is dissolved in organic solvent. A knownamount of the active drug is suspended (insoluble drugs) or co-dissolved(soluble drugs) in the polymer solution. The solution or the dispersionis then spray-dried. Typical process parameters for a mini-spray drier(Buchi) are as follows: polymer concentration=0.04 g/mL, inlettemperature=−24° C., outlet temperature=13-15 □C, aspirator setting=15,pump setting=10 mL/minute, spray flow=600 Nl/hr, and nozzle diameter=0.5mm. Microparticles ranging between 1-10 microns are obtained with amorphology which depends on the type of polymer used.

Hydrogel Microparticles.

Microparticles made of gel-type polymers, such as alginate, are producedthrough traditional ionic gelation techniques. The polymers are firstdissolved in an aqueous solution, mixed with barium sulfate or somebioactive agent, and then extruded through a microdroplet formingdevice, which in some instances employs a flow of nitrogen gas to breakoff the droplet. A slowly stirred (approximately 100-170 RPM) ionichardening bath is positioned below the extruding device to catch theforming microdroplets. The microparticles are left to incubate in thebath for twenty to thirty minutes in order to allow sufficient time forgelation to occur. Microparticle particle size is controlled by usingvarious size extruders or varying either the nitrogen gas or polymersolution flow rates. Chitosan microparticles can be prepared bydissolving the polymer in acidic solution and crosslinking it withtripolyphosphate. Carboxymethyl cellulose (CMC) microparticles can beprepared by dissolving the polymer in acid solution and precipitatingthe microparticle with lead ions. In the case of negatively chargedpolymers (e.g., alginate, CMC), positively charged ligands (e.g.,polylysine, polyethyleneimine) of different molecular weights can beionically attached.

3. Methods of Encapsulating or Attaching Molecules to the Surface of theParticles

There are two principle groups of molecules to be encapsulated orattached to the polymer, either directly or via a coupling molecule:targeting molecules, attachment molecules and therapeutic, nutritional,diagnostic or prophylactic agents. These can be coupled using standardtechniques. The targeting molecule or therapeutic molecule to bedelivered can be coupled directly to the polymer or to a material suchas a fatty acid which is incorporated into the polymer.

Functionality refers to conjugation of a ligand to the surface of theparticle via a functional chemical group (carboxylic acids, aldehydes,amines, sulfhydryls and hydroxyls) present on the surface of theparticle and present on the ligand to be attached. Functionality may beintroduced into the particles in two ways.

The first is during the preparation of the microparticles, for exampleduring the emulsion preparation of microparticles by incorporation ofstablizers with functional chemical groups.

A second is post-particle preparation, by direct crosslinking particlesand ligands with homo- or heterobifunctional crosslinkers. This secondprocedure may use a suitable chemistry and a class of crosslinkers (CDI,EDAC, glutaraldehydes, etc. as discussed in more detail below) or anyother crosslinker that couples ligands to the particle surface viachemical modification of the particle surface after prepartion. Thissecond class also includes a process whereby amphiphilic molecules suchas fatty acids, lipids or functional stabilizers may be passivelyadsorbed and adhered to the particle surface, thereby introducingfunctional end groups for tethering to ligands.

B. Pharmaceutical Compositions

Pharmaceutical compositions including particles are provided.Pharmaceutical compositions can be for administration by parenteral(intramuscular, intraperitoneal, intravenous (IV) or subcutaneousinjection), transdermal (either passively or using iontophoresis orelectroporation), or transmucosal (nasal, vaginal, rectal, orsublingual) routes of administration or using bioerodible inserts andcan be formulated in dosage forms appropriate for each route ofadministration.

In some embodiments, the compositions are administered systemically, forexample, by intravenous or intraperitoneal administration, in an amounteffective for delivery of the compositions to targeted cells. Otherpossible routes include trans-dermal or oral.

In certain embodiments, the compositions are administered locally, forexample by injection directly into a site to be treated. Typically,local injection causes an increased localized concentration of thecompositions which is greater than that which can be achieved bysystemic administration. In some embodiments, the compositions aredelivered locally to the appropriate cells by using a catheter orsyringe. Other means of delivering such compositions locally to cellsinclude using infusion pumps (for example, from Alza Corporation, PaloAlto, Calif.) or incorporating the compositions into polymeric implants(see, for example, P. Johnson and J. G. Lloyd-Jones, eds., Drug DeliverySystems (Chichester, England: Ellis Horwood Ltd., 1987), which caneffect a sustained release of the particles to the immediate area of theimplant.

The particles can be provided to the cell either directly, such as bycontacting it with the cell, or indirectly, such as through the actionof any biological process. For example, the particles can be formulatedin a physiologically acceptable carrier or vehicle, and injected into atissue or fluid surrounding the cell. The particles can cross the cellmembrane by simple diffusion, endocytosis, or by any active or passivetransport mechanism.

As further studies are conducted, information will emerge regardingappropriate dosage levels for treatment of various conditions in variouspatients, and the ordinary skilled worker, considering the therapeuticcontext, age, and general health of the recipient, will be able toascertain proper dosing. The selected dosage depends upon the desiredtherapeutic effect, on the route of administration, and on the durationof the treatment desired. Generally dosage levels of 0.001 to 10 mg/kgof body weight daily are administered to mammals. Generally, forintravenous injection or infusion, dosage may be lower. Generally, thetotal amount of the particle-associated active agent administered to anindividual will be less than the amount of the unassociated active agentthat must be administered for the same desired or intended effect.

1. Formulations for Parenteral Administration

In a preferred embodiment the particles are administered in an aqueoussolution, by parenteral injection. The formulation can be in the form ofa suspension or emulsion. In general, pharmaceutical compositions areprovided including effective amounts of one or more active agentsoptionally include pharmaceutically acceptable diluents, preservatives,solubilizers, emulsifiers, adjuvants and/or carriers. Such compositionscan include diluents sterile water, buffered saline of various buffercontent (e.g., Tris-HCl, acetate, phosphate), pH and ionic strength; andoptionally, additives such as detergents and solubilizing agents (e.g.,TWEEN® 20, TWEEN® 80 also referred to as polysorbate 20 or 80),anti-oxidants (e.g., ascorbic acid, sodium metabisulfite), andpreservatives (e.g., Thimersol, benzyl alcohol) and bulking substances(e.g., lactose, mannitol). Examples of non-aqueous solvents or vehiclesare propylene glycol, polyethylene glycol, vegetable oils, such as oliveoil and corn oil, gelatin, and injectable organic esters such as ethyloleate. The formulations may be lyophilized and redissolved/resuspendedimmediately before use. The formulation may be sterilized by, forexample, filtration through a bacteria retaining filter, byincorporating sterilizing agents into the compositions, by irradiatingthe compositions, or by heating the compositions.

2. Formulations for Topical and Mucosal Administration

The particles can be applied topically. Topical administration caninclude application to the lungs, nasal, oral (sublingual, buccal),vaginal, or rectal mucosa. These methods of administration can be madeeffective by formulating the shell with transdermal or mucosal transportelements. For transdermal delivery such elements may include chemicalenhancers or physical enhancers such as electroporation or microneedledelivery. For mucosal delivery PEGylation of the outer shell or additionof chitosan or other mucosal permeants or PH protective elements fororal delivery.

Compositions can be delivered to the lungs while inhaling and traverseacross the lung epithelial lining to the blood stream when deliveredeither as an aerosol or spray dried particles having an aerodynamicdiameter of less than about 5 microns.

A wide range of mechanical devices designed for pulmonary delivery oftherapeutic products can be used, including but not limited tonebulizers, metered dose inhalers, and powder inhalers, all of which arefamiliar to those skilled in the art. Some specific examples ofcommercially available devices are the Ultravent® nebulizer(Mallinckrodt Inc., St. Louis, Mo.); the Acorn® II nebulizer (MarquestMedical Products, Englewood, Colo.); the Ventolin® metered dose inhaler(Glaxo Inc., Research Triangle Park, N.C.); and the Spinhaler® powderinhaler (Fisons Corp., Bedford, Mass.). Nektar, Alkeiines and Mannkindall have inhalable insulin powder preparations approved or in clinicaltrials where the technology could be applied to the formulationsdescribed herein.

Formulations for administration to the mucosa will typically be spraydried drug particles, which may be incorporated into a tablet, gel,capsule, suspension or emulsion. Standard pharmaceutical excipients areavailable from any formulator. Oral formulations may be in the form ofchewing gum, gel strips, tablets, capsules, or lozenges. Oralformulations may include excipients or other modifications to theparticle which can confer enteric protection or enhanced deliverythrough the GI tract, including the intestinal epithelia and mucosa (seeSamstein, et al. Biomaterials. 29(6):703-8 (2008).

Transdermal formulations may also be prepared. These will typically beointments, lotions, sprays, or patches, all of which can be preparedusing standard technology. Transdermal formulations can includepenetration enhancers. Chemical enhancers and physical methods includingelectroporation and microneedles can work in conjunction with thismethod.

III. Methods of Use

A. Treatment Strategy

As discussed in more detail below, the disclosed compositions andmethods are particularly useful in the context of immune suppression andinduction and maintenance of immune tolerance. By efficiently deliveringboth TGF-β and IL-2 to CD4 T cells, this platform circumvents severalfundamental drawbacks of today's leading autoimmune therapies. Paracrinecytokine delivery can 1) increase Treg induction signaling in-vitro andin-vivo, 2) enhance suppressive function, 3) retained Foxp3 expressioneven in depolarizing conditions, or combinations thereof.

Functional Tregs are critical for maintaining self-tolerance andpreventing autoimmunity, but effective therapies that harness Tregfunction remain elusive. The Examples below demonstrate thatbiodegradable nanoparticles can enhance the ability of combination TGF-βand IL-2 to generate functional and stable Tregs.

Administration of regulatory cytokines to treat autoimmune pathologieshas proven to be a promising strategy. Specifically, the administrationof low-dose recombinant IL-2 can reverse type 1 diabetes in NOD mice byexpanding natural Treg numbers. In humans, IL-2 therapy has achievedclinical benefit in a small number of patients with graft-versus-hostdisease or vasculitis. Drawbacks to this approach arise from thepleiotropic nature of IL-2, which also induces proliferation of naturalkiller cells and CD8 effector T cells. Additionally, recombinant IL-2has a short half-life in circulation, requiring frequent doses tomaintain its affect while minimizing off-target signaling. One strategyto overcome IL-2 induced lymphocyte proliferation involves theco-administration of suppressive drugs such as rapamycin. Whilerapamycin is thought to work primarily by inhibiting IL-2-mediatedproliferation specifically in T effector cells, it also induces TGF-βproduction in lymphocytes. Rapamycin/IL-2 therapy indeed preventedeffector T cell proliferation in a clinical trial, but both naturalkiller cell and eosinophil numbers were enhanced, and beta cell functiondeclined. These adverse effects reflected toxicity associated withsystemic mTOR inhibition and off-target IL-2 signaling. The disclosednanoparticles compositions and methods of use thereof directly deliverboth IL-2 and TGF-β to T cells, bypassing systemic toxicity.

In some embodiments, nanoparticles are loaded with a ratio (1:2) ofIL-2:TGF-β targeted to CD4 cells and can signal cooperatively at thecell surface. TGF-β, a regulatory cytokine recognized as a Treg inducer,can be used in conjunction with IL-2 to generate CD4 Tregs in-vitro. TheExamples below show that the efficiency of Treg induction afterincubation with TGF-β and IL-2 was maintained after prior depletion ofnTregs, showing that the cytokine combination can induce thedifferentiation of naïve Foxp3− CD4 T cells. Thus in some embodiments,the particles are administered in an effective amount to induce thedifferentiation of naïve Foxp3− CD4 T cells.

It is believed that sustained release of both cytokines illustrated inthe Examples below was comparable due to physiochemical similaritiesbetween both proteins. To verify preservation of each cytokine'sstructure following PLGA encapsulation and particle synthesis,bioactivity was assayed during particle-mediated release. Encapsulatedcytokines displayed greater bioactivity compared to solublecounterparts. Enhanced bioactivity may be due to increased localconcentration gradients, and this has been observed with encapsulatedIL-2. Strikingly, with encapsulated TGF-β, not only was the signalingthreshold reduced, but the Foxp3 induction plateau was increased,highlighting the impact of high local concentration gradients.

Thus, the nanoparticle-mediated paracrine-delivery of IL-2 and TGF-β maybe more effective at driving naïve CD4 cells to become Tregs. Forexample, paracrine signaling reveals that diffusive cytokine transfermay trigger signaling outcomes through reorganization of membranereceptors. Thus in some embodiments, the particles are administered inan effective amount to induce naïve CD4 cells to become Tregs. TGF-βsignaling requires surface dimerization of two receptor subunits, whichmay partially depend on this paracrine affect, leading to the observedenhancement by nanoparticle-mediated delivery.

In addition to more efficient generation of Foxp3+ Tregs, the Examplesillustrate that nanoparticles induce Tregs that are more effectivesuppressors on a per cell basis. When Foxp3+ Treg cell numbers werematched between soluble cytokine-induced suppressors andnanoparticle-generated suppressors, nanoparticle-induced suppressorsshowed superior ability to inhibit CD4 effector proliferation inresponse to TCR ligation and costimulation. This effect was retaineddown to 1/32 initial Treg fraction, and verified that nanoparticlebinding to the Treg cell surface had no detrimental impact on theirfunctional capacity, but facilitated enhanced function. In theseexperiments, nanoparticle-induced suppressor cells retained Foxp3expression to a greater extent than soluble cytokine-induced suppressorcells, which showed no correlation between initial Treg fraction andfinal Foxp3 expression. This observation supports the conclusion thatnanoparticle-mediated delivery of TGF-β and IL-2 blocks the loss ofFoxp3 expression over time. Thus in some embodiments, the particles areadministered in an effective amount to reduce the loss of Foxp3expression over time.

Results of the Foxp3 kinetic assays exemplified below indicate thatnanoparticle-mediated delivery of TGF-β and IL-2 may also help overcomeT cell plasticity in the context of inflammation and typically observedwith Treg cell therapy. Although adoptive transfer of ex-vivo inducedTregs are effective at treating diabetes in NOD mice, a growing body ofwork indicates that these cells can turn off Foxp3 expression and evenrevert to an effector phenotype within inflammatory environments.Nanoparticle delivery can maintain local cytokine availability totargeted cells even within polarizing microenvironments, which is usefulfor maintenance of Foxp3 expression in the absence of endogenousregulatory factors.

The Examples also illustrate that systemic administration ofCD4-targeted nanoparticles results in accumulation, in secondarylymphoid tissues, making encapsulated cytokines available during T celldifferentiation. Indeed, systemic administration of CD4-targetedTGF-β+IL-2 nanoparticles enhances Treg frequency in these tissues.

B. Methods of Treatment

The disclosed methods typically include using CD4-targeted particlesloaded with TGF-β+IL-2, to deliver the cytokines into cells, or to acell's microenvironment. The methods typically include contacting theTGF-β+IL-2 agent-loaded particles with one more cells. The contactingcan occur in vivo or in vitro. The compositions can be administered tothe subject therapeutically or prophylactically. Exemplary therapeuticand prophylactic strategies are discussed in more detail below and inthe Examples.

Immune cells, preferably T cells, can be contacted in vivo or ex vivowith TGF-β+IL-2-loaded particles to decrease or inhibit immune responsesincluding, but not limited to inflammation. The T cells can include anycell which express the T cell receptor, including α/β and γ/δ T cellreceptors. T-cells include all cells which express CD3, including T-cellsubsets which also express CD4 and CD8. T-cells include both naïve andmemory cells and effector cells such as CTL. T-cells also includeregulatory cells such as Th1, Tc1, Th2, Tc2, Th3, Th17, Th22, Treg, andTr1 cells. T-cells also include NKT-cells and similar unique classes ofthe T-cell lineage. In some embodiments, the cells express or arcinduced to express CD4+, Foxp3+, CD25+, or any combination thereof.

In the most preferred embodiments, the particles are contacted with (1)Treg in an effective amount to induce, enhance, or maintain a regulatoryphenotype or a combination thereof, (2) effector T cells in an effectiveamount to reduce effector function, induce transdifferentiation into aTreg, or a combination thereof; or a combination of (1) and (2). In someembodiments, the methods increase the number of Tregs, for example,percentage of Tregs in a total CD4+ population. In some embodiments, thenumber or ratio of Foxp3+ Tregs in increased. In some embodiments, thenumber or ratio (relative to total CD4+) of effector cells is reduced ornot increased.

For example, the compositions be used to increase or promote theactivity of Tregs, increase the production of cytokines such as IL-10from Tregs, increase the differentiation of Tregs, increase the numberof Tregs, or increase the survival of Tregs. The compositions can beused to directly or indirectly modulate Th1, Th17, Th22, or other cellsthat secrete, or cause other cells to secrete, inflammatory molecules,including, but not limited to, IL-1β, TNF-α, TGF-beta, IFN-γ, IL-17,IL-6, IL-23, IL-22, IL-21, and MMPs.

In some embodiments, the disclosed compositions are administered incombination with a second therapeutic. Combination therapies may beuseful in immune modulation. In some embodiments, the compositions canbe used to attenuate or reverse the activity of a pro-inflammatory drug,and/or limit the adverse effects of such drugs.

Administration of a drug or other cargo to cells or a subject usingparticles can be compared to a control, for example, delivery of theTGF-β, IL-2 and/or other cargo to cells or a subject using conventionaldelivery methods such as free cargo/drug delivery, or delivery usingconventional liposomal methods such as LIPOFECTAMINE®. Particles can beused to deliver cargo to target cells with increased efficacy comparedto conventional delivery methods. In some embodiments less cargo or drugis required when delivered using particles compared to conventionaldelivery methods to achieve the same or greater therapeutic benefit.

In some embodiments toxicity is reduced or absent compared toconventional delivery methods. For example, in some embodiments, whiteblood cell, platelet, hemoglobin, and hematocrit levels were withinnormal physiological ranges; no liver or renal toxicities are observed;body weight and serum concentrations for alkaline phosphatase, alaninetransferase, total bilirubin, and blood urea nitrogen are normal; orcombinations thereof following administration of loaded particles to thesubject.

1. In Vivo Methods

The disclosed compositions can be used in a method of delivering activeagents to cells in vivo. In some in vivo approaches, the compositionsare administered to a subject in a therapeutically effective amount. Asused herein, the term “effective amount” or “therapeutically effectiveamount” means a dosage sufficient to treat, inhibit, or alleviate one ormore symptoms of the disorder being treated or to otherwise provide adesired pharmacologic and/or physiologic effect. The precise dosage willvary according to a variety of factors such as subject-dependentvariables (e.g., age, immune system health, etc.), the disease, and thetreatment being effected. In some embodiments, the subject hasinflammation, an inflammatory disease or disorder, an autoimmune, or isa subject for or a recipient of transplantation, as discussed in moredetail below.

a. Drug Delivery

The particles can be used to deliver an effective amount of TGF-β andIL-2 alone or in combination with one or more therapeutic, diagnostic,and/or prophylactic agents to an individual in need of such treatment.The amount of agent to be administered can be readily determine by theprescribing physician and is dependent on the age and weight of thepatient and the disease or disorder to be treated.

The particles are useful in drug delivery (as used herein “drug”includes therapeutic, nutritional, diagnostic and prophylactic agents),whether injected intravenously, subcutaneously, or intramuscularly,administered to the nasal or pulmonary system, injected into a tumormilieu, administered to a mucosal surface (vaginal, rectal, buccal,sublingual), or encapsulated for oral delivery. The particles may beadministered as a dry powder, as an aqueous suspension (in water,saline, buffered saline, etc), in a hydrogel, organogel, in capsules,tablets, troches, or other standard pharmaceutical excipient

An exemplary embodiment is a dry powder rehydrated with the capsulant ofinterest in sterile saline or other pharmaceutically acceptableexcipient.

As discussed herein, compositions can be used to as delivery vehiclesfor a number of active agents including small molecules, nucleic acids,proteins, and other bioactive agents. The active agent or agents can beencapsulated within, dispersed within, and/or associated with thesurface of the particle. In some embodiments, the particle packages two,three, four, or more different active agents for simultaneous deliveryto a cell.

b. Transfection

The disclosed compositions can be for cell transfection ofpolynucleotides. For example, in some embodiments, the TGF-β and IL-2are delivered as a polynucleotide (e.g., mRNA or a vector, etc.,encoding the TGF-β+IL-2) that can be expressed by the cells upontransfection. In some embodiments, other polynucleotides are utilized aspart of the therapy. As discussed in more detail below, the transfectioncan occur in vitro or in vivo, and can be applied in applicationsincluding gene therapy and disease treatment. The compositions can bemore efficient, less toxic, or a combination thereof when compared to acontrol. In some embodiments, the control is cells treated with analternative transfection reagent such as LIPOFECTAMINE 2000.

Polynucleotides delivered by the particles can be selected by one ofskill in the art depending on the condition or disease to be treated.The polynucleotide can be, for example, a gene or cDNA of interest, afunctional nucleic acid such as an inhibitory RNA, a tRNA, an rRNA, oran expression vector encoding a gene or cDNA of interest, a functionalnucleic acid a tRNA, or an rRNA. The polynucleotides expresses or induceexpression of TGF-β and/or IL-2 in cells.

In some embodiments two or more polynucleotides are administered incombination. Thus TGF-β and IL-2 can be co-delivered with otherpolynucleotide drugs. In some embodiments, the polynucleotide encodes aprotein. Exemplary proteins include, for example, (a) angiogenic andother factors including growth factors such as acidic and basicfibroblast growth factors, vascular endothelial growth factor,endothelial mitogenic growth factors, epidermal growth factor,transforming growth factor α and β, platelet-derived endothelial growthfactor, platelet-derived growth factor, tumor necrosis factor-α,hepatocyte growth factor and insulin-like growth factor; (b) cell cycleinhibitors such as cyclin-dependent kinases, thymidine kinase (“TK”),and other agents useful for interfering with cell proliferation; (c)bone morphogenic proteins (“BMP's”), including BMP-2, BMP-3, BMP-4,BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1), BMP-8, BMP-9, BMP-10, BMP-11,BMP-12, BMP-13, BMP-14, BMP-15, and BMP-16. BMPs are typically dimericproteins that can be provided as homodimers, heterodimers, orcombinations thereof, alone or together with other molecules.Alternatively, or in addition, molecules capable of inducing an upstreamor downstream effect of a BMP can be provided. Such molecules includeany of the “hedgehog” proteins, or the DNA's encoding them.

In some embodiments, the polynucleotide is not integrated into the hostcell's genome (i.e., remains extrachromosomal). Such embodiments can beuseful for transient or regulated expression of the polynucleotide, andreduce the risk of insertional mutagenesis. Therefore, in someembodiments, the particles are used to deliver mRNA or non-integratingexpression vectors that are expressed transiently in the host cell.

In some embodiments, the polynucleotide is integrated into the hostcell's genome. For example, gene therapy is a technique for correctingdefective genes responsible for disease development. Researchers may useone of several approaches for correcting faulty genes: (a) a normal genecan be inserted into a nonspecific location within the genome to replacea nonfunctional gene. This approach is most common; (b) an abnormal genecan be swapped for a normal gene through homologous recombination; (c)an abnormal gene can be repaired through selective reverse mutation,which returns the gene to its normal function; (d) the regulation (thedegree to which a gene is turned on or off) of a particular gene can bealtered.

Gene therapy can include the use of viral vectors, for example,adenovirus, adeno-associated virus, herpes virus, vaccinia virus, poliovirus, AIDS virus, neuronal trophic virus, Sindbis and other RNAviruses, including these viruses with the HIV backbone. Also useful areany viral families which share the properties of these viruses whichmake them suitable for use as vectors. Typically, viral vectors contain,nonstructural early genes, structural late genes, an RNA polymerase IIItranscript, inverted terminal repeats necessary for replication andencapsidation, and promoters to control the transcription andreplication of the viral genome. When engineered as vectors, virusestypically have one or more of the early genes removed and a gene orgene/promoter cassette is inserted into the viral genome in place of theremoved viral DNA.

2. In Vitro Methods

The disclosed compositions can be used in a method of delivering activeagents to cells in vitro. For example, the compositions can be used toinduce, expand, or enhance Treg numbers, suppressive effect, orstabilize Foxp3 expression ex vivo, for use, for example in Tregtherapy. In some embodiments, TGF-β+IL-2 is delivered to the cells in aneffective amount to change the genotype or a phenotype of the cell. Thusthe compositions can be used in methods of Adoptive Cell Transfer (ACT).ACT refers to the transfer of cells into a patient. As discussed in moredetail below, cells can originated from the patient and treated ex vivobefore being transferred back. They can also originate from anotherindividual. The cells are most commonly derived from the immune system,with the goal of transferring improved immune functionality andcharacteristics along with the cells back to the patient. In someembodiments, the subject has inflammation, an inflammatory disease ordisorder, an autoimmune, or is a subject for or a recipient oftransplantation, as discussed in more detail below.

The disclosed compositions and methods are particular useful in thecontext of adoptive Treg therapy. Applications for Treg therapy areknown in the art and include, for example, treatment of inflammation,autoimmune disease, graft rejection and other conditions discussedherein and known in the art. See, for example, Nagahama, et al., MethodsMol 2007; 380:431-42, which discusses that CD4+CD25+ regulatory T (Treg)cells can be exploited to establish immunologic tolerance to allogeneictransplants.

The cells can be primary cells isolated from a subject, or cells of anestablished cell line. The cells can be of a homogenous cell type, orcan be a heterogeneous mixture of different cells types. For example,the particles can be introduced into the cytoplasm of cells from aheterogenous cell line possessing cells of different types, such as in afeeder cell culture, or a mixed culture in various states ofdifferentiation. The cells can be a transformed cell line that can bemaintained indefinitely in cell culture.

The methods are particularly useful in the field of personalizedtherapy, for example to de-differentiate cells, transdifferentiatecells, differentiate cells, reprogram cells, enhance or prolong thefunction of cells, and/or reduce or prevent the de-differentiation,transdifferentiation, or differentiation of cells. For example, targetcells are first isolated from a donor using methods known in the art,contacted with the particle including TGF-β+IL-2 causing a change to thein vitro (ex vivo), and administered to a patient in need thereof.Sources or cells include cells harvested directly from the patient or anallographic donor. In preferred embodiments, the target cells to beadministered to a subject will be autologous, e.g. derived from thesubject, or syngenic. Allogeneic cells can also be isolated fromantigenically matched, genetically unrelated donors (identified througha national registry), or by using target cells obtained or derived froma genetically related sibling or parent.

Cells can be selected by positive and/or negative selection techniques.For example, antibodies binding a particular cell surface protein may beconjugated to magnetic beads and immunogenic procedures utilized torecover the desired cell type. It may be desirable to enrich the targetcells prior to transient transfection. As used herein in the context ofcompositions enriched for a particular target cell, “enriched” indicatesa proportion of a desirable element (e.g. the target cell) which ishigher than that found in the natural source of the cells. A compositionof cells may be enriched over a natural source of the cells by at leastone order of magnitude, preferably two or three orders, and morepreferably 10, 100, 200, or 1000 orders of magnitude. Once target cellshave been isolated, they may be propagated by growing in suitable mediumaccording to established methods known in the art. Established celllines may also be useful in for the methods. The cells can be storedfrozen before transfection, if necessary.

Next the cells are contacted with the disclosed composition in vitro torepair, de-differentiate, re-differentiate, and/or re-program the cell.The cells can be monitored, and the desired cell type can be selectedfor therapeutic administration. For examples, in some embodiments thedisclosed methods are be used to change the phenotype of immune cells.

Following repair, de-differentiation, and/or re-differentiation and/orreprogramming, the cells are administered to a patient in need thereof.In the most preferred embodiments, the cells are isolated from andadministered back to the same patient. In alternative embodiments, thecells are isolated from one patient, and administered to a secondpatient. The method can also be used to produce frozen stocks of alteredcells which can be stored long-term, for later use.

C. Diseases to Be Treated

1. Inflammatory Responses

A preferred embodiment provides methods for treating or alleviating oneor more symptoms of inflammation. In some embodiments, the compositionsand methods disclosed are useful for treating chronic and persistentinflammation. Inflammation in general can be treated using the disclosedTGF-β+IL-2-loaded particles.

An immune response including inflammation can be inhibited or reduced ina subject, preferably a human, by administering an effective amount ofTGF-β+IL-2-loaded particles to inhibit or reduce the biological activityof an immune cell or to reduce the amounts of proinflammatory moleculesat a site of inflammation. Exemplary proinflammatory molecules include,but are not limited to, IL-1β, TNF-α, TGF-beta, IFN-γ, IL-17, IL-6,IL-23, IL-22, IL-21, and MMPs.

TGF-β+IL-2-loaded particles can cause Tregs to have an enhancedsuppressive effect on an immune response. Tregs can suppressdifferentiation, proliferation, activity, and/or cytokine productionand/or secretion by Th1, Th17, Th22, and/or other cells that secrete, orcause other cells to secrete, inflammatory molecules, including, but notlimited to, IL-1β, TNF-α, TGF-beta, IFN-γ, IL-17, IL-6, IL-23, IL-22,IL-21, and MMPs. For example, TGF-β+IL-2-loaded particles can causeTregs to have an enhanced suppressive effect on Th1 and/or Th17 cells toreduce the level of IFN-γ and IL-17 produced, respectively.TGF-β+IL-2-loaded particles can cause Tregs to promote or enhanceproduction of IL-10 to suppress the Th1 and Th17 pathway, or to increasethe number of Tregs.

The TGF-β+IL-2-loaded particles can also be administered to a subject inan amount effective to increase Treg cell populations or numbers orratios relative to other cell types. In some embodiments, theTGF-β+IL-2-loaded particles increases the population or number or ratioof Fox3P+ Tregs, for example, relative to total CD4+ cells.

In some embodiments, IL-10 and/or TGF-β production by Tregs is increasedrelative to a control by contacting the Tregs with an effective amountof TGF-β+IL-2-loaded particles. The increase can occur in vitro or invivo.

Administration is not limited to the treatment of existing conditions,diseases or disorders (i.e. an existing inflammatory or autoimmunedisease or disorder) but can also be used to prevent or lower the riskof developing such diseases in an individual, i.e., for prophylacticuse. Potential candidates for prophylactic vaccination includeindividuals with a high risk of developing an inflammatory or autoimmunedisease or disorder, i.e., with a personal or familial history ofcertain types of autoimmune disorders.

The compositions can be administered to subject in need thereof in anamount effective to treat an inflammatory or autoimmune disease ordisorder. Representative inflammatory or autoimmune diseases anddisorders that may be treated using TGF-β+IL-2-loaded particles include,but are not limited to, rheumatoid arthritis, systemic lupuserythematosus, alopecia areata, anklosing spondylitis, antiphospholipidsyndrome, autoimmune Addison's disease, autoimmune hemolytic anemia,autoimmune hepatitis, autoimmune inner ear disease, autoimmunelymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura(ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiacsprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome(CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricialpemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease,Dego's disease, dermatomyositis, dermatomyositis—juvenile, discoidlupus, essential mixed cryoglobulinemia, fibromyalgia—fibromyositis,grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathicpulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iganephropathy, insulin dependent diabetes (Type I), juvenile arthritis,Meniere's disease, mixed connective tissue disease, multiple sclerosis,myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritisnodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica,polymyositis and dermatomyositis, primary agammaglobulinemia, primarybiliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome,rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-mansyndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis,ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener'sgranulomatosis.

2. Transplant Rejection

A preferred embodiment provides methods for reducing or inhibitingtransplant rejection in a subject, preferably a human subject.Transplant rejection can be inhibited or reduced in a subject byadministering an effective amount of TGF-β+IL-2-loaded particles toinhibit or reduce the biological activity of an immune cell or to reducethe amounts of proinflammatory cytokines or other molecules associatedwith or that promote inflammation at a site of transplant. Exemplaryproinflammatory molecules include, but are not limited to IL-1β, TNF-α,TGF-beta, IFN-γ, IL-17, IL-6, IL-23, IL-22, IL-21, and MMPs.

Administration is not limited to the treatment of existing conditions,diseases or disorders (i.e. an existing inflammatory or autoimmunedisease or disorder) but can also be used to prevent or lower the riskof developing such diseases in an individual, i.e., for prophylacticuse. Thus, the disclosed composition can be administered prior totransplant, during transplant, and after transplant.

The transplanted material can be cells, tissues, organs, limbs, digitsor a portion of the body, preferably the human body. The transplants aretypically allogenic or xenogenic. The disclosed compositions areadministered to a subject in an effective amount to reduce or inhibittransplant rejection. Particles can be administered systemically orlocally by any acceptable route of administration. In some embodiments,the compositions are administered to a site of transplantation prior to,at the time of, or following transplantation. In one embodiment, theparticles are administered to a site of transplantation parenterally,such as by subcutaneous injection.

In other embodiments, particles are administered directly to cells,tissue or organ to be transplanted ex vivo. In one embodiment, thetransplant material is contacted with TGF-β+IL-2-loaded particles priorto transplantation, after transplantion, or both.

In other embodiments, TGF-β+IL-2-loaded particles are administered toimmune tissues or organs, such as lymph nodes or the spleen.

The transplant material can be treated with enzymes or other materialsthat remove cell surface proteins, carbohydrates, or lipids that areknown or suspected in being involved with immune responses such astransplant rejection.

a. Cells

Populations of any types of cells can be transplanted into a subject.The cells can be homogenous or heterogenous. Heterogeneous means thecell population contains more than one type of cell. Exemplary cellsinclude progenitor cells such as stem cells and pluripotent cells whichcan be harvested from a donor and transplanted into a subject. The cellsare optionally treated prior to transplantation as mention above. Suchtreatment includes transfecting the cells ex vivo with particles loadedwith TGF-β+IL-2 or a nucleic acid construct enabling the cells toexpress TGF-β+IL-2 in vitro and in vivo.

Exemplary cells that can be transplanted include, but are not limitedto, islet cells, hematopoietic cells, muscle cells, cardiac cells,neural cells, embryonic stem cells, adult stem cells, T cells,lymphocytes, dermal cells, mesoderm, endoderm, and ectodeini cells.

b. Tissues

Any tissue can be used as a transplant. Exemplary tissues include skin,adipose tissue, cardiovascular tissue such as veins, arteries,capularies, valves; neural tissue, bone marrow, pulmonary tissue, oculartissue such as corneas and lens, cartilage, bone, and mucosal tissue.

c. Organs

Exemplary organs that can be used for transplant include, but are notlimited to kidney, liver, heart, spleen, bladder, lung, stomach, eye,tongue, pancreas, intestine, etc. The organ to be transplanted can alsobe modified prior to transplantation as discussed above.

One embodiment provides a method of inhibiting or reducing chronictransplant rejection in a subject by administering an effective amountof a TGF-β+IL-2-loaded particles to inhibit or reduce chronic transplantrejection relative to a control.

3. Graft-Versus-Host Disease (GVHD)

The disclosed TGF-β+TL-2-loaded particles can also be used to treatgraft-versus-host disease (GVHD) by administering an effective amount ofthe composition to alleviate one or more symptoms associated with GVHD.GVHD is a major complication associated with allogeneic hematopoieticstem cell transplantation in which functional immune cells in thetransplanted marrow recognize the recipient as “foreign” and mount animmunologic attack. It can also take place in a blood transfusion undercertain circumstances. Symptoms of GVD include skin rash or change inskin color or texture, diarrhea, nausea, abnormal liver function,yellowing of the skin, increased susceptibility to infection, dry,irritated eyes, and sensitive or dry mouth.

4. Diabetes

The TGF-β+IL-2-loaded particles can also be used to treat diabetes. Themethod includes transplanting insulin producing cells in a subject andadministering to the subject an effective amount of TGF-β+IL-2-loadedparticles to reduce or inhibit transplant rejection. Preferably theinsulin producing cells are beta cells or islet cells. In certainembodiments, the insulin producing cells are recombinant cellsengineered to produce insulin.

The insulin producing cells can be encapsulated within a matrix, such asa polymeric matrix, using suitable polymers, including, but not limitedto alginate, agarose, hyaluronic acid, collagen, synthetic monomers,albumin, fibrinogen, fibronectin, vitronectin, laminin, dextran, dextransulfate, chondroitin sulfate, dermatan sulfate, keratan sulfate, chitin,chitosan, heparan, heparan sulfate, or a combination thereof.

D. Combination Therapy

The disclosed compositions can be used alone or in combination withadditional therapeutic agents. The additional therapeutic agentsinclude, but are not limited to, immunosuppressive agents (e.g.,antibodies against other lymphocyte surface markers (e.g., CD40, alpha-4integrin) or against cytokines), other fusion proteins (e.g., CTLA-4-Ig(Orencia®), TNFR-Ig (Enbrel®)), TNF-α blockers such as Enbrel, Remicade,Cimzia and Humira, cyclophosphamide (CTX) (i.e. Endoxan®, Cytoxan®,Neosar®, Procytox®, Revimmune™), methotrexate (MTX) (i.e. Rheumatrex®,Trexall®), belimumab (i.e. Benlysta®), or other immunosuppressive drugs(e.g., cyclosporin A, FK506-like compounds, rapamycin compounds, orsteroids), anti-proliferatives, cytotoxic agents, or other compoundsthat may assist in immunosuppression.

In a preferred embodiment, the additional therapeutic agent functions toinhibit or reduce T cell activation and cytokine production through aseparate pathway. In one such embodiment, the additional therapeuticagent is a CTLA-4 fusion protein, such as CTLA-4 Ig (abatacept). CTLA-4Ig fusion proteins compete with the co-stimulatory receptor, CD28, on Tcells for binding to CD80/CD86 (B7-1/B7-2) on antigen presenting cells,and thus function to inhibit T cell activation. In a preferredembodiment, the additional therapeutic agent is a CTLA-4-Ig fusionprotein known as belatacept. Belatacept contains two amino acidsubstitutions (L104E and A29Y) that markedly increase its avidity toCD86 in vivo. In another embodiment, the additional therapeutic agent isMaxy-4.

In another embodiment, the second therapeutic agent preferentiallytreats chronic transplant rejection or GvHD, whereby the treatmentregimen effectively targets both acute and chronic transplant rejectionor GvHD. In a preferred embodiment the second therapeutic is a TNF-αblocker.

In another embodiment, the second therapeutic agent increases the amountof adenosine in the serum, see, for example, WO 08/147482. In apreferred embodiment, the second therapeutic is CD73-Ig, recombinantCD73, or another agent (e.g. a cytokine or monoclonal antibody or smallmolecule) that increases the expression of CD73, see for example WO04/084933. In another embodiment the second therapeutic agent isInterferon-beta.

In a preferred embodiment, the compositions are used in combination orsuccession with compounds that increase Treg activity or production.Exemplary Treg enhancing agents include but are not limited toglucocorticoid fluticasone, salmeteroal, antibodies to IL-12, IFN-γ, andIL-4; vitamin D3, and dexamethasone, and combinations thereof.Antibodies to other proinflammatory molecules can also be used incombination or alternation with the TGF-β+IL-2-loaded particles.Preferred antibodies bind to IL-6, IL-23, IL-22 or IL-21.

As used herein the term “rapamycin compound” includes the neutraltricyclic compound rapamycin, rapamycin derivatives, rapamycin analogs,and other macrolide compounds which are thought to have the samemechanism of action as rapamycin (e.g., inhibition of cytokinefunction). The language “rapamycin compounds” includes compounds withstructural similarity to rapamycin, e.g., compounds with a similarmacrocyclic structure, which have been modified to enhance theirtherapeutic effectiveness. Exemplary Rapamycin compounds are known inthe art (See, e.g. WO95122972, WO 95116691, WO 95104738, U.S. Pat. Nos.6,015,809; 5,989,591; U.S. Pat. Nos. 5,567,709; 5,559,112; 5,530,006;5,484,790; 5,385,908; 5,202,332; 5,162,333; 5,780,462; 5,120,727).

The language “FK506-like compounds” includes FK506, and FK506derivatives and analogs, e.g., compounds with structural similarity toFK506, e.g., compounds with a similar macrocyclic structure which havebeen modified to enhance their therapeutic effectiveness. Examples ofFK506-like compounds include, for example, those described in WO00101385. Preferably, the language “rapamycin compound” as used hereindoes not include FK506-like compounds.

Other suitable therapeutics include, but are not limited to,anti-inflammatory agents. The anti-inflammatory agent can benon-steroidal, steroidal, or a combination thereof. One embodimentprovides oral compositions containing about 1% (w/w) to about 5% (w/w),typically about 2.5% (w/w) or an anti-inflammatory agent. Representativeexamples of non-steroidal anti-inflammatory agents include, withoutlimitation, oxicams, such as piroxicam, isoxicam, tenoxicam, sudoxicam;salicylates, such as aspirin, disalcid, benorylate, trilisate, safapryn,solprin, diflunisal, and fendosal; acetic acid derivatives, such asdiclofenac, fenclofenac, indomethacin, sulindac, tolmetin, isoxepac,furofenac, tiopinac, zidometacin, acematacin, fentiazac, zomepirac,clindanac, oxepinac, felbinac, and ketorolac; fenamates, such asmefenamic, meclofenamic, flufcnamic, niflumic, and tolfenamic acids;propionic acid derivatives, such as ibuprofen, naproxen, benoxaprofen,flurbiprofen, ketoprofen, fenoprofen, fenbufen, indopropfen, pirprofen,carprofen, oxaprozin, pranoprofen, miroprofen, tioxaprofen, suprofen,alminoprofen, and tiaprofenic; pyrazoles, such as phenylbutazone,oxyphenbutazone, feprazone, azapropazone, and trimethazone. Mixtures ofthese non-steroidal anti-inflammatory agents may also be employed.

Representative examples of steroidal anti-inflammatory drugs include,without limitation, corticosteroids such as hydrocortisone,hydroxyl-triamcinolone, alpha-methyl dexamethasone,dexamethasone-phosphate, beclomethasone dipropionates, clobetasolvalerate, desonide, desoxymethasone, desoxycorticosterone acetate,dexamethasone, dichlorisone, diflorasone diacetate, diflucortolonevalerate, fluadrenolone, fluclorolone acetonide, fludrocortisone,flumethasone pivalate, fluosinolone acetonide, fluocinonide, flucortinebutylesters, fluocortolone, fluprednidene (fluprednylidene) acetate,flurandrenolone, halcinonide, hydrocortisone acetate, hydrocortisonebutyrate, methylprednisolone, triamcinolone acetonide, cortisone,cortodoxone, flucetonide, fludrocortisone, difluorosone diacetate,fluradrenolone, fludrocortisone, diflurosone diacetate, fluradrenoloneacetonide, medrysone, amcinafel, amcinafide, betamethasone and thebalance of its esters, chloroprednisone, chlorprednisone acetate,clocortelone, clescinolone, dichlorisone, diflurprednate, flucloronide,flunisolide, fluoromethalone, fluperolone, fluprednisolone,hydrocortisone valerate, hydrocortisone cyclopentylpropionate,hydrocortamate, meprednisone, paramethasone, prednisolone, prednisone,beclomethasone dipropionate, triamcinolone, and mixtures thereof.

The present invention will be further understood by reference to thefollowing non-limiting examples.

EXAMPLES

McHugh, et al., “Paracrine co-delivery of TGF-β and IL-2 usingCD4-targeted nanoparticles for induction and maintenance of regulatory Tcells,” Biomaterials, 59:172-81 (2015).doi:10.1016/j.biomaterials.2015.04.003. Epub 2015 May 15, isspecifically incorporated by references herein in its entirety.

Example 1: Nanoparticle Fabrication and Characterization Materials andMethods

Nanoparticle Synthesis

Human recombinant TGF-β1 (mammalian-derived, Peprotech, Rocky Hill,N.J.) and human recombinant IL-2 (Proleukin) was encapsulated inavidin-coated PLGA nanoparticles using a water/oil/water emulsiontechnique as previously described (35). Briefly, 2.5 μg of aqueouscytokine solution was added drop-wise while vortexing to 50 mg PLGA(50:50 monomer ratio, Durect Corp) in 3 mls chloroform. The resultingemulsion was added dropwise to 3 mls of water containing 3% poly-vinylalcohol (Sigma-Aldrich) and 0.625 mg/ml avidin-palmitate conjugate(previously described elsewhere (35)). This double emulsion was thensonicated to create nano-sized droplets of chloroform containingencapsulated cytokine, within aqueous surfactant. Solvent was removed bymagnetic stirring at room temperature for 3 hours. Hardenednanoparticles were then washed 3 times in MilliQ water and lyophilizedfor long-term storage. Nanoparticles were prepared fresh fromlyophilized stocks for each experiment. Briefly, nanoparticles weredispersed in PBS at 10 mg/ml by vortexing and 2-3 seconds of bathsonication. CD4-targeted nanoparticles were formed by reactingavidin-coated nanoparticles in PBS with 2 μg biotin-anti-CD4 (RM 4-5,eBiosciences) per mg NP for 15 minutes and used immediately.

Characterization of Nanoparticle Size and Morphology

Nanoparticle morphology was analyzed via scanning electron microscopy(SEM). Samples were sputter-coated with gold using a Dynavac Mini Coaterand imaged with a Hitachi SU-70 SEM with an accelerating voltage of 5kV. Particle size was quantified using the Nanosight particle trackingsystem (NanoSight, Ltd., Wiltshire, UK). Cytokine release was measuredby incubating 1.0 mg nanoparticles in 1 ml PBS at 37° C. and measuringcytokine concentration in supernatant fractions over time by ELISA.

Imaging of T Cell-NP Interactions

10 μg of DiR-encapsulating nanoparticles conjugated to CD4 or isotypeantibodies was added to C57BL/6 splenocytes (1.0×106/ml) and tumbled for15 minutes at 37° C. in 1.5 ml microcentrifuge tubes. Cells were thenstained for CD4-PE and analyzed using an Amnis Imagestream instrument.

Cell Culture

All cell culture was performed at 37° C., 5.0% CO2, 100% humidity inRPMI-1640 (Life Technologies) supplemented with 10% FBS (AtlantaBiologics), Pen/Strep, L-glutamine, MEM Vitamin solution, non-essentialamino acids, sodium pyruvate, and beta-mercaptoethanol (LifeTechnologies).

Results

PLGA nanoparticles encapsulating TGF-β and IL-2 were visualized usingscanning electron microscopy (SEM). Nanoparticles are spherical inmorphology and range in size from less than 100 nm to 300 nm.Quantitative size analysis was performed using the NANOSIGHT® particletracking system, which confirmed the size distribution and revealed amean particle size of 168 nm (FIG. 1A).

To measure the release kinetics of encapsulated cytokines over thecourse of nanoparticle degradation, the particles were incubated in PBSand ELISAs were performed on their supernatants over time. The resultingplot indicates a burst release of TGF-β and IL-2 over the first 4 days,followed by linear release for the next 14 days (FIG. 1B). At day 5 ofincubation, 0.8 ng and 0.5 ng of TGF-β and IL-2, respectively, arereleased from each mg of nanoparticles. To verify the binding capacityof anti-CD4-conjugated nanoparticles to CD4 T cells,1,1′-Dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine iodide, AATBioquest (DiR) labeled, anti-CD4-conjugated nanoparticles were incubatedwith mixed splenocytes. Following incubation, cells were stained forCD4-PE and analyzed using Amnis ImageStream Cytometry to visualize theparticles' CD4 specificity and cellular localization. Targeting withanti-CD4 increases specific binding from 10.8% to 61.6%, while thepercentage of CD4+ cells tagged with nanoparticles is enhanced from3.97% to 73.9%. Nanoparticles bind to the outer membrane of CD4 T cells.In all subsequent experiments, nanoparticles are coated with anti-CD4unless otherwise stated.

Example 2: Nano-Encapsulated Cytokines Generate Foxp3+ CD4 Tregs

Materials and Methods

Functional Characterization of Nano-Encapsulated IL-2

CRL-1841 cells (ATCC, Manassas, Va.) were seeded at 5.0×104 cells perwell of a 96-well plate and dosed with free IL-2 or IL-2 encapsulated inuntargeted nanoparticles. Fold proliferation was quantified by CoulterCounter after 4 days of culture.

Animals

C57BL/6 and BALB/c mice were purchased from Jackson Labs and Harlan,respectively, for use at 6-12 weeks of age. Mice expressing GFP as areporter of Foxp3 expression (GFP-Foxp3 reporter mice) were generated ona C57BL/6 background as previously described (Bettelli, et al., Nature,441(7090):235-8 (2006). All animal work was performed under protocolsapproved by the Yale Institute of Animal Care and Use Committee.

In-Vitro Treg Expansion

Freshly isolated mouse splenocytes were plated in 96-well round bottomplates at 1.0×105 cells in 0.2 ml per well. Wells were pre-coated withanti-CD3 (eBiosciences) at 2.0 ug/ml and media was supplemented with 2.0ug/ml anti-CD28 (eBiosciences). For Treg induction conditions, media wassupplemented with TGF-β and IL-2 at 5.0 ng/ml and 10 ug/ml,respectively, unless otherwise stated. For kinetic analysis of Foxp3expression, cells were removed from culture at day 3, washed twice inmedia to remove unbound nanoparticles and free cytokine, and re-seededin fresh wells containing CD3 and CD28. For Foxp3 destabilizingconditions, TGF-β and IL-6 were added at re-seeding at 5.0 and 10 ng/ml,respectively. Nanoparticles were prepared as described above and addedto cells at 100 ug/ml, unless otherwise stated.

Results

Foxp3-GFP reporter mouse splenocytes were depleted of CD4+CD25+Foxp3+cells by FACS. Cells were stimulated with anti-CD3 and anti-CD28 in thepresence of TGF-I3 and IL-2 for three days. Foxp3+CD4+ cells aregenerated in both the nTreg depleted and non-depleted groups (18.9% and21.9% of lymphocytes, respectively), indicating that TGF-β and IL-2induce Foxp3 expression from naïve CD4 cells. After 5 days of Treginduction by either nano-encapsulated or free TGF-β and IL-2, cellssecreted TGF-β and IL-10 as measured by ELISA (FIG. 2A). RepresentativeFACS plots show that Foxp3 expression is increased by nearly 2-foldusing nano-encapsulated IL-2 and TGF-β compared to soluble cytokines.Cumulative data from four independent experiments shows significantdifferences between each group (FIG. 2B). Dose response curves show thatlower concentrations of TGF-β released from 0.1 mg/ml targeted oruntargeted nanoparticles is needed for Foxp3 expression compared tosoluble TGF-β (FIG. 2C). IL-2 dependent cells require 10 fold less IL-2released from nanoparticles in comparison with soluble IL-2 forequivalent proliferation (FIG. 2D).

Example 3: Functional Properties of Nanoparticle-Induced Tregs

Staining, FACS, and Cytokine Secretion Analysis

Cells were stained with CellTrace Violet (Life Technologies) followingthe manufacturers suggested protocol. After red blood cell lysis,splenocyte pellets were resuspended in 10 uM solution of CellTraceViolet in DPBS and incubated for 15 minutes at 37° C. The reaction wasthen quenched using 5× volume of RPMI+10% FBS, and cells were pelletedonce more to wash away free CellTrace Violet dye. For the Tregsuppressor assay (FIG. 4A-4E), responder cells were labeled withCellTrace Violet after FACS purification and plated immediately.

Fluorescent antibodies were purchased from eBiosciences and used indilutions of 1:200 or 1:400 in FACS buffer (PBS containing 2% FBS) forsurface staining. CD4 was detected using clone RM 4-4 to avoidcompetitive binding with nanoparticle-conjugated RM 4-5. Cells wereincubated with antibodies for 20-30 minutes and washed once in FACSbuffer. For experiments requiring Foxp3 staining, samples were treatedwith 250 ul of Fix/Perm buffer (Intracellular Fixation andPermeabilization Kit, eBiosciences) after washing off surfaceantibodies. After 30-60 minutes, samples were washed with 2.0 mls Pennbuffer and incubated with Foxp3 antibody (clone FJK-16s, eBioscience)for 30-60 minutes. Cells were then washed with 2.0 mls Penn buffer.After staining, cells were suspended in 1% PFA until FACS analysis up to24 hours later. All incubations in the immunostaining procedures werecarried out in the dark on ice. FACS analysis was performed on either aFACScan or LSR-II (Becton Dickinson), and sorting was done on a FACSAria(Becton Dickinson). All FACS data were analyzed using FlowJo software(Tree Star Inc., Ashland, Oreg.).

TGF-β and IL-10 secretion was quantified by ELISA using kits purchasedfrom Becton Dickinson, following the manufacturer's suggestedinstructions. Total TGF-β was measured by activating latent cytokine byincubating supernatants with 0.04 N HCl for 1 hour and neutralizing withNaCl. TGF-β supplied by the treatment was subtracted from the measuredvalues to quantify secretion.

Treg Suppression Assay

Tregs were generated from Foxp3-GFP reporter mouse (Thy1.1−) splenocytesusing either soluble TGF-β and IL-2 or nano-encapsulated TGF-β and IL-2for a 5 day induction period beginning with 1×105 cells per well in96-well U-bottom plates. At the end of culture, the percentage ofCD4+Foxp3+ Tregs in each group was quantified by FACS. Cells were washedof excess nanoparticles or cytokines by centrifugation. These cells,defined collectively as the suppressor population, were mixed withFACS-purified, CellTrace Violet labeled Thy1.1+CD4+CD25− splenocytes,(defined as responder cells) at titrated frequencies and stimulated withCD3/CD28 beads (Dynabeads, Life Technologies) at a 1:2 bead-to-cellratio for 4 days in 96-well flat-bottom plates. Samples were surfacestained for CD4 and Thy1.1 and run on FACS immediately.

Proliferative Index was calculated by dividing the total number ofresponder cells at the end of culture by the number of parent respondercells. Total number of cells was calculated by gating on each generationand accounting for number of divisions, using an area under the curvesummation formula previously reported (Roederer, et al., Cytometry PartA: the journal of the International Society for Analytical Cytology,79(2):95-101. PubMed PMID: 21265003) and defined in Table 2. InitialTreg frequency, or the percentage of Thy1.1-Foxp3+ Tregs in culture atthe start of the suppression phase is defined in Table 2.

Results

To test the effect of nanoparticle treatment on TCR-mediated cellactivation, naïve CD4 cells were stimulated using CD3/CD28 coatedpolystyrene beads. Even under these strong effector T cell stimulatoryconditions, where Treg induction is mitigated, nanoparticle treatmentsignificantly enhanced Foxp3 expression (FIG. 3A) and inhibited effectorcell proliferation (FIG. 3B), compared to soluble cytokine controls.CD4-targeted empty nanoparticles had minimal effects.

To test suppressive function, induced Tregs were washed and culturedunder CD3/CD28 stimulation with responder Thy1.1+ CD4 cells at variousrelative fractions over a four-day period referred to as the suppressionphase. For clarity, each cell population is referred to using asuperscript/subscript notation defined in Table 1. Characterizationterms are defined in Table 2.

TABLE 1 Superscript/subscript notation Notation A_(y) ^(x) where: A iseither the frequency f in terms of percentage, or number N of cells persample well x is the parent population from which A is gated y describesthe given population For Example: N_(1.1+) ^(CD4) = Number of Cells (N)per sample from a Thy1.1+ cell population that are CD4⁺. or; f_(1.1+)^(CD4) = Percent frequency (f) per sample from a Thy1.1⁺ cell populationthat are CD4⁺. Notation Definition N_(1.1+) ^(CD4) Final number (perwell) of responder cells (Thy1.1⁺) N_(1.1+,i) ^(CD4) Initial number (perwell) of responder cells (Thy1.1⁺) N_(1.1−) ^(CD4) Final number (perwell) of suppressor cells (Thy1.1⁺) f_(1.1+) ^(CD4) Final frequency (%)of responder cells (Thy1.1⁺) from all CD4 f_(1.1+,i) ^(CD4) Initialfrequency (%) of responder cells (Thy1.1⁺) from all CD4 f_(1.1−) ^(CD4)Final frequency (%) of suppressor cells (Thy1.1⁻) from all CD4f_(1.1−Foxp3,i) ^(CD4) Initial frequency (%) of Foxp3⁺ suppressor cells(Thy1.1⁻) from all CD4 f_(Foxp3+) ^(1.1−) Final frequency (%) of Foxp3⁺cells from suppressor (Thy1.1⁻) population N_(Foxp3+) ^(1.1−) Finalnumber (per well) of Foxp3⁺ cells from suppressor (Thy1.1⁻) populationN_(Foxp3+,i) ^(1.1−) Initial number (per well) of Foxp3⁺ cells fromsuppressor (Thy1.1⁻) population

TABLE 2 Characterization of terms Term Definition Proliferative index,PI   Initial Treg fraction^(b)   Final Treg number (per well),N_(Foxp3+) ^(1.1−) $\quad\begin{matrix}{= {\sum_{0}^{g}{f_{g}^{1.1 +}/{\sum_{0}^{g}( {f_{g}^{1.1 +}/2^{g}} )^{a}}}}} \\{= {f_{{1.1 - {{Foxp}\mspace{11mu} 3} +},i}^{{CD}\; 4}/( {f_{{1.1 - {{foxp}\mspace{11mu} 3} +},i}^{CD4} + f_{{1.1 +},i}^{CD4}} )}} \\{= {({PI}) \times ( {f_{1.1 -}^{CD4}/100} ) \times ( {f_{{{Foxp}\mspace{11mu} 3} +}^{1.1 -}/100} )^{C} \times 10^{5}}}\end{matrix}$ ^(a)Where g is generation number (0 is undividedpopulation) and f_(g) is frequency of events in generation g.^(b)“Initial” refers to the start of the suppression phase (day 5).^(c)N_(Foxp3+, i) ^(1.1−) + N_(1.1+, i) ^(CD4) = 10⁵

A schematic of the experimental procedure as a representative cellresponse over time is shown (FIG. 4A (left)). At the end of thesuppression phase, the resulting CD4 pool was characterized by plottingThy1.1 expression vs. CellTrace Violet incorporation as shown in arepresentative FACS plot (FIG. 4A (center)). Suppressor cells wereidentified by absence of CellTrace Violet and Thy1.1 expression, andResponder cells were identified as Thy1.1+ CellTrace Violetintermediate-to-high, representing proliferated and undivided cells,respectively. Responder cells were plotted on a histogram according toCellTrace Violet incorporation and gated for generation number as shownin a representative histogram (FIG. 4A (right)). Representativehistograms from each initial Treg fraction from each group show reducedCellTrace Violet dilutions in nanoparticle-treated groups (FIG. 4B).Proliferative Indices calculated from the above data are graphed,revealing significantly lower responder cell proliferation innanoparticle groups at all initial Treg fractions tested (FIG. 4C).Nanoparticle-treated suppressor cells also retained Foxp3 expression toa greater extent to those induced using soluble cytokines. Foxp3quantifications are plotted over initial Treg fraction, showing thatgreatest relative Foxp3 expression is found at ½ initial Treg fractions,approximately 3-fold higher than soluble controls (FIG. 4D). Absolutenumber of Foxp3+Tregs within the suppressor population is calculated asdescribed in Table 2 and plotted separately (FIG. 4E). The trend isretained, in which higher initial Treg fraction correlates with Foxp3expression in the nanoparticle groups more closely than in solublegroups.

Example 4: Foxp3 Stability of Nanoparticle-Induced Tregs

In-vitro kinetics assays were performed to test the phenotype stabilityof nanoparticle-induced Tregs. Mixed splenocyte cultures were incubatedwith free or CD4-targeted nano-encapsulated cytokine before replacementwith fresh media after 3 days. As a positive control, free cytokineswere replenished at day 3. By day 9 of culture, Foxp3 expression bysoluble cytokine-induced cells was nearly completely lost (98% less thanday 5), while Foxp3 expressing nanoparticle-induced Tregs diminished byonly 34% from day 5 (FIG. 5). To evaluate Foxp3 stability underinflammatory insult, the Th17-polarizing cytokine combination TGF-β/IL-6was added to the cultures after a 5-day Treg induction phase. At day 7,the number of CD25+Foxp3+ CD4 cells was largely retained in thenanoparticle-induced cells.

Example 5: Expansion of Tregs In-Vivo

Materials and Methods

In-Vivo Biodistribution and Treg Quantification

6-8 week old female C57/B16 mice received coumarin-6 loadednanoparticles via intraperitoneal injection on day 0. On day 5, micewere sacrificed and secondary lymphoid tissues were collected, includingthe spleen, axial lymph nodes (aLN), mesenteric lymph nodes (mLN), andinguinal lymph nodes (iLN). For analysis of coumarin-6 loadednanoparticle biodistribution, whole spleen or lymph samples werehomogenized and subjected to 3 freeze/thaw cycles prior tolyophilization. Coumarin 6 was extracted by incubation of homogenizedtissues in DMSO and quantified using standards generated in tissues fromuntreated mice, by fluorescence with excitation/emission at 460/540 nm.

For Treg quantification, tissues were processed and stained for CD4,CD25, and Foxp3 as previously described and analyzed by FACS. Cells werecounted using a Coulter Counter.

Results

Next the effects of nanoparticle-mediated cytokine delivery wereinvestigated in vivo. The biodistribution of CD4-targeted nanoparticleswas investigated using coumarin 6 (C6)-loaded nanoparticles. Micereceived a dose of 2.0 mgs of nanoparticles administered viaintraperitoneal injection. After 5 days, animals were sacrificed andsecondary lymphoid organs were collected for analysis. Extraction of C6from the tissues showed the highest accumulation in the spleen anddraining (mesenteric) lymph nodes (FIG. 6A). To assess the ability ofnanoparticles to expand Tregs in-vivo, mice were injected with 2.0 mgCD4-targeted nanoparticles. After 5 days, lymph nodes were collected andTreg induction was assessed by FACS. In comparison to naïve animals(left hand bars), nanoparticle-treated animals (right hand bars) had asignificantly higher frequency of Tregs in the mesenteric lymph node andspleen as measured by their frequency within the CD4 T cell compartment(FIG. 6B) (n=5 mice, *p<0.05). Total numbers of activated T cells andTregs were not significantly enhanced (FIG. 6C).

Modifications and variations of the compositions and methods ofmanufacture and use thereof will be obvious to those skilled in the artfrom the foregoing detailed description and are intended to come withinthe scope of the appended claims. All references are specificallyincorporated.

I claim:
 1. A method of increasing donor specific Treg comprisingtreating isolated cells ex vivo with a composition comprisingCD4-targeted nanoparticles loaded with a combination of TGF-β and IL-2.